Other Population Characteristics

In terms of marital status of the population 20 years old and over in 2007, there are 4,841 single or 20.2% of the total population of the age range which is 24,016. There are more single males than females with a ratio of 183 males per 100 females. Sixty percent of those 20 years old and over is married, 8.2% is widowed, 1.6% is divorced/separated, 9.8% is common-law/live-in and 0.2% is of unknown marital status.

A vast majority of households or 98.9% speaks Bikol as language at home. Only 0.88% of households speaks Tagalog at home followed by Bisaya at 0.08%. The people of Irosin are mostly Christian where 96.22% of the total population is Roman Catholic, 1.52% is Iglesia ni Kristo and 0.074% is affiliated with the UCCP. The rest are distributed into different denominations.

In 2007, of the total population of 5 years old and over of 42,923, 26.84% is in elementary grade level, 16.83% is elementary graduate, 15.77% is high school undergraduate, 16.11% is high school graduate, 5.36% is college undergraduate, 5.56% is academic degree holder while only 0.11% has post baccalaureate education. There are more female academic degree holders than male with a ratio of 78 males for every 100 females. The literacy rate of 10 years old and over is 98% in 2015.




Population Growth and Distribution

Irosin population has grown from 8,644 in 1903 to 56,662 in 2015 with a cumulative increase of 48,018 or 556%.  Within the span of 112 years the population rose at an annual average rate of 1.68% per year. The population has practically doubled from the 1970 population to the present 2015 population or 45 years. The growth rate for the census period 2010 and 2015 is 1.72%. At this present growth rate, the doubling time of population is 40 years.

The 2015 urban population is 14,389 or 25.47% of the total population while the rural population is 42,273 or 74.6% of the total population. In the 2007 NSO census, 2,688 households or 27% of the total households are in the urban area while 7,225 are in the rural barangays. The most populated barangay is the urban barangay of Bacolod with a population of 4,518 in 2015. The second and third most populous are the rural barangays of Monbon and Gabao with populations of 4,414 and 4,286 respectively. The urbanization level, or growth in the proportion of population living in urban barangays, has been steadily declining in the past 20 years. This declining trend is correlated to the disparity in the population growth rate of rural and urban barangays. The annual growth rate of urban barangays from the 1980 to 2015 ranged from -0.70% to 1.15%, while the rural barangay’s growth rate ranged from 1.41% to 2.98% in the same period.

The gross population density of the municipality is 3.75 persons per hectares in 2010. Urban density is 45.2 persons per hectare compared to the rural density of 2.86 persons per hectare. The highest density of population is found in Bacolod with 245.85 persons per hectare, followed by San Juan, San Julian, San Agustin and San Pedro. The built-up density of urban barangays is almost the same as its gross population density except for San Pedro which has a large tract of agricultural lands. For the rural barangays, the highest density is Gabao with a population density of 10.67 persons per hectare and followed by Gulang-gulang, Macawayan, Buenavista and Batang with densities of 9.16, 8.88, 6.45 and 5.59 respectively. The built-up density of rural barangays is significantly lower since habitation areas are usually clustered on small areas surrounded by vast agricultural lands.




Population

Population Composition

Irosin has a total population of 56,662 in 2015, comprising 7.1% of Sorsogon province total population. There are 11,820 documented households for the same year and the average household size is 4.64.  The population has grown by 4,885 persons from 2010 with an average annual growth rate of 1.72%. 

Irosin’s population is expansive. In 2010, the age group below one year to 14 years old comprises 38.6% of the total population. The productive population with ages ranging from 15 to 64 years old is 56.3% of the population while the proportion of senior citizens or 65 years old and above is 5.1% of the population. Male population is slightly higher than the female population in 2010 where there are 103.3 males for every 100 females. The local age-sex distribution follows a worldwide pattern in which males predominate at birth but the ratio gradually declines with increasing age presumably because males have higher age-specific mortality rates. Consequently, females tend to outnumber males as their age advances. For the age group 65 and above, the ratio is 66 males for every 100 females.

The total age dependency ratio in 2010, or the ratio of those who are too young (below 15 years old) and too old (65 years and above) to earn a living to the productive population (15 to 64 years old), is 74 dependents for every 100 productive individuals. The young dependency ratio is 69 young dependents for every 100 productive individuals while the elderly dependency ratio is 6 out of 100.

The number of labor force in the age group 15 years old and over is 61% of the population in 2010. Of the total labor force, there are 15,259 total gainful workers documented in 2010. The sex ratio of the employed population is 330 employed males for every 100 employed females.

The school-going population ages three to 20 years old is 44% of the total population in 2010. The proportion of pre-school age (3 to 5 years old) to the total population is 7.5%, the elementary school age (6 to 11 years old) is 15.8%, the secondary school age (12 to 15 years old) is 10.3% while the tertiary school age (16 to 20 years old) is 10.4% of the total population.

Population, Number of Households per Barangay, 2015

No. BARANGAY POPULATION (NSO 2015) HOUSEHOLD (2015)
Urban Barangays      
1 Bacolod 4,518 954
2 San Agustin 2,125 429
3 San Juan 2,161 474
4 San Julian 2,431 519
5 San Pedro 3,154 706
Sub-Total   14,389 3,082
Rural Barangays      
6  Bagsangan 2,961 667
7 Batang 2,231 484
8 Bolos 882 187
9 Buenavista 1,320 272
10 Bulawan 1,149 240
11 Carriedo 3,197 670
12 Casini 1,155 244
13 Cawayan 428 114
14 Cogon 1,164 266
15 Gabao 4,286 777
16 Gulang-gulang 2,925 600
17 Gumapia 719 169
18 Liang 943 200
19 Macawayan 2,873 595
20 Mapaso 860 180
21 Monbon 4,414 805
22 Patag 3,136 676
23 Salvacion 1,427 281
24 San Isidro 720 152
25 Sto. Domingo 950 226
26 Tabon-tabon 1,628 312
27 Tinampo 1,489 318
28 Tongdol 1,376 343
Sub-Total   42,273 9,138
TOTAL =->> 56,662 11,820