Estimates and Future Projections of Demography

The projected population at the start of the planning period in 2018 is 59,658. Assuming a constant annual growth of 1.72%, the projected population in 2028 is 70,835. There are 12,613 projected number of households in 2018 which will grow to 14,976 in 2028. Urban population is projected to be 15,150 in 2018 and 17,988 in 2028. The number of people living in the rural barangays will increase from 44,508 in 2018 to 52,847 by 2028. The doubling time, or the time required for Irosin’s population to double itself given the present fixed growth rate of 1.72% is 40 years. (Refer to Table DE-11)

By 2018, the school age going population is projected to be 27,003 and will be 32,098 in 2028. Population of elementary and secondary level school age will be 10,206 and 9,842 in 2028 respectively. Dependent population will reach 29,171 in 2028 with 25,420 young dependents 0 to 14 years old and 3,750 old dependents 65 years and over. The projected population of the labor force 15 years and over in 2018 is 38,108 and 45,247 in 2028. (Refer to Table DE-12)

Population Change

Historical Growth of Population

Irosin’s population has grown from 8,644 in 1903 to 56,662 in 2015 with a cumulative increase of 48,081 or 556%. In this 112 years period, the average growth rate of the population is 1.68% per year. From the first census in 1903 to 1918, the population grew by 3.39% annually. There was a sharp decline in growth in the period 1918 to 1939 that rebounded back up to 1.79% annually by 1980. From 1980, there was again a decline to 1990 and increasing trend up to 2.23% by 2000. There is a decreasing trend in annual population growth rate from a high of 3.39% in the period 1903 to 1918 to the present 1.72% for 2010 to 2015. Historically, the growth rate of Irosin is lower than the national and provincial growth rate. For 2000 to 2010 period, Irosin’s annual growth rate of 1.29% is lower than the national growth of 1.90%, the regional growth of 1.46%, and the provincial growth rate of 1.31%. (Refer to Table DE-6)


Fertility and Mortality

The simplest and most commonly used index of fertility is the Crude Birth Rate (CBR) which is the number of births divided by population expressed in thousands. In 2016, the CBR of the municipality is 21 or 23 live births per 1,000 of population. The local trend in CBR fluctuates during the last five years but is generally on the range of 20 to 25 and fertility is generally decreasing. Mortality or the occurrence of death is roughly measured by the Crude Death Rate (CDR) which is the number of deaths per 1,000 of population. The 2016 CDR is 6.38 deaths per 1,000 of population. The CDR of Irosin for the past five years ranges from 7.95 to 6.38 and mortality rate is generally decreasing. Irosin’s CBR in 2013 is 22.6 which is lower than the national CBR of 24.4 in the same year. For CDR, the national rate is 6.52 in 2016 which is higher than the local CDR of 6.38. (Refer to Table DE-7)

The average rate of natural increase (RNI) in population, which is the difference between CBR and CDR, is 1.47% for the past five years. Since the population growth rate is higher than the rate of natural increase, the population is not closed and it is assumed that 0.25% of the growth rate is net of in-migration and out-migration.


Commerce and Trade

There are 463 registered businesses from the tertiary sector in 2016 which are engaged in trade, transportation, finance and business service, and community, social and personal services. Majority of these establishments are wholesale and retail stores selling various kinds of merchandise including meat, fish and vegetable dealers. There are also service shops, eateries, bakeries, food processors, drugstores, and amusement centers and video shops. Buying stations are found along M. L. Quezon Street where copra, palay and abaca are traded. Agricultural supplies, automotive parts dealers, appliance dealers and gasoline/refilling stations are also thriving. Trading and business transaction in Irosin are concentrated mainly at the Central Business District (CBD) in the town center. The highlights of CBD are the Irosin Public Market, Municipal Hall, Public Auditorium and the line of commercial establishments where commodity trading stations, wholesale and retail variety stores, banks and service shops are found. Presently, a commercial strip is growing from the corner of J. P. Rizal and M. L. Quezon Streets stretching all the way to the Maharlika Highway.

The financial institutions in Irosin are the Land Bank of the Philippines, Rural Bank of Irosin, East-West Rural Bank, Camalig Bank, Card Bank and Rural Bank of Guinobatan. The Land Bank of the Philippines-Irosin Branch caters to a wide range of customers from local government units, cooperatives as well as commercial and industrial establishments from micro to large enterprises. The bank likewise accept savings, current and time deposits and foreign currency exchange particularly dollar and serves as a collecting agency of the Bureau of Internal Revenue (BIR), Social Security System (SSS) and Philippine Health Insurance. There are also many microfinancing institutions in Irosin namely ARDCI NGO Group, ASA Philippines Foundation, Equalshare Credit Corporation, First Consolidate Bank, First Inner Trade Credit Corporation as well as cooperatives offering financing services.

The increasing population in the rural barangays led to the setting up of barangays centers where public markets, chapel, health centers, barangay halls and multi-purpose pavements are normally clustered. Such centers are located in the barangays of Gabao, Batang, Monbon, Patag and Gulang-Gulang. Of the convergence areas Gabao is the most progressive.

Other Population Characteristics

Labor Force Population and Employment

The labor force population, or those 15 years and over, is 36,194 or 64% of the total population in 2015. Of these, 52% are employed while 48% are not employed . Of all males 15 years and above, 73% are employed while only 30% are female. The provincial employment rate is at 56%. The local unemployment rate in 2013 is 17.9% . Of the 18,646 gainfully employed population, 28% are laborers and unskilled worker, 22% are skilled agricultural workers, 15% are service and sales workers, 8% are craft and related trades workers. (Refer to Table DE-9)


Literacy, Educational Attainment and Attendance to School

In 2015, 99% of Irosin’s population ten years old and over is literate, with both males and females at 99% literacy. The provincial literacy rate is also at 99%. Of the 5 years old and over population of 49, 801, 38.9% are in elementary grade level, 39% at high school level, 14.1% are elementary graduate, 21.5% are high school graduate, 7.4% are college undergraduate, 7.9% are academic degree holder while only 0.1% has post baccalaureate education. There are more female academic degree holders than male with a ratio of 73 males for every 100 females. Of the 24,872 with ages 5 to 24 years old, only 74% are attending school. The school participation rate for 7 to 12 years old is estimated to be 97% and only 78% for ages 13 to 18 years old. There are more males attending school at 104 male to female ratio. (Refer to Table DE-8)


Marital Status, Household Size and Religions Affiliations

The marital status of the 43,102 ten years old and over population is 48.1% single, 34.6% married, 11.1% common law/live-in, and 5.1% widowed 5.1%. There are more single males with 122 male to 100 female ratio. The sex ratio for those with married status is 96 males per 100 male. Half of those 20 years old and over is married, 25.8% are single, 7.4% are widowed, 1.5% is divorced/separated and 15.3% is common-law/live-in. Of the population below 20 years old, 98% are single.

Of the PSA enumerated 11,418 households in 2015, 38% are with 5 to 7 members, 31% with 3 to 4, 16% with 1 to 2 members and there are 15% or 1,693 households with 8 and above members. The PSA average household size is 5.0.

The religious affiliation of Sorsogon province population is predominantly Christian, with 94.29% Roman Catholic, 1.77% Iglesia ni Cristo and the rest are distributed in other religious affiliation. Language spoken at home in Sorsogon province in 2010 is 98.9% Bikol, 0.9% Tagalog, 0.1% Bisaya and 0.1% Maranao.

Environmentally Critical Areas

The environmentally critical areas in the municipality under Presidential Proclamation No. 2146 are the NIPAS areas, timberlands, areas that are prone and vulnerable to natural hazards, areas with critical slopes, areas classified as prime agricultural lands and water bodies.

The Bulusan Volcano mountain ranges including Mt. Agoho and Mt. Jormajan on the northern section have the largest constrained area where there is overlapping of NIPAS lands, the permanent danger zone, pyroclastic flow hazard zones and areas with slope of 30%. Critical slopes can also be found in the Mt. Maraot Banwa in Cawayan, Tabon-tabon and Carrideo as well as in Salvacion adjoining Buenavista and San Isidro.  Other areas of critical slopes are in Casini near the boundary with Matnog and in hilly areas in Batang, Gumapia and Tongdol. The areas in the lower elevation at the valley floor that are prone to flooding during heavy rains are also considered under this category. The banks or easement of rivers and creeks are part of water bodies and are therefore constrained areas.    

Timberlands not yet declared as alienable and disposable lands in Tabon-tabon, Cawayan, Bolos and Liang with a total of 76.4970 hectares are also considered as constrained areas. Prime agricultural lands are the Network of Protected Agricultural Areas or Network of Areas for Agricultural Development (NPAA/NAAD) of Irosin that falls under ECA category. These are agricultural lands that are protected from any form of conversion so as to keep and preserve the highly suitable agricultural land for primary food crops. In this regard, the existing irrigated and potentially irrigable rice lands of 2,128.39 hectares of the municipality falls under this land resource category.

The total environmentally constrained area in the municipality is estimated to be 7,625.823 hectares which represents 51% of the total land area.