Demographics
Population and Households
The population of Irosin as of May 1, 2020 was 59,267 based on the 2020 PSA Census of Population. Irosin’s population is higher by 2,605 compared to 2015 population. The population growth rate from 2015 to 2020 is 0.95% which is lower compared to the 2010 to 2015 growth rate of 1.72%. Irosin’s population accounted for 6.8% of Sorsogon Province population and ranked sixth in terms of population size. There are 12,753 households in the same year with an average household size of 4.65. From the 2015-2020 growth rate, the population for year 2023 is projected to be 61,719.
Population Composition
Irosin’s population is expansive, that is, a very large proportion of population belongs to the younger age group. The age group below one year to 14 years old accounted for 34.5% of the total population. There is a trend of decreasing fertility as the proportion of this age group declined from 42% in 2000, to 39% in 2010 and to 34.5% in 2020. The productive population with ages ranging from 15 to 64 years old comprise 59.5% of the total population. Senior citizens accounted for 5.9% of the population. Male population is slightly higher than the female population with 100 males for every 97 females. the age group 65 and above, the ratio is 64 males for every 100 females in 2015. The total dependency ratio, or the ratio of those who are too young (below 15 years old) and too old (65 years and above), to those who are 15 to 64 years, is 68 dependents and for every 100 productive individuals. The proportion of those in the working age 15 to 54 years is 59% of the population.
Table 1. Total Population, Number of Households, Average Household Size, Gross Area and Gross Density by Barangay as of May 1, 2020
Population Distribution and Density
The 2020 urban population is 14,620 or 24.7% of the total population while the rural population is 44,647 or 75.3% of the total population. The most populated barangay is the urban barangay of Bacolod with 4,645, followed by the rural barangays of Gabao with 4,499, Monbon with 4,293, Carriedo with 3,675, and Gulang-Gulang with 3,468 population. Irosin’s gross population density is 392 persons per square kilometer or 3.92 persons per hectare. Urban density is at 46 persons per hectare compared to rural density of 3. The highest population density is found in urban barangays of Bacolod with 253 persons per hectare, followed by San Juan at 199, San Agustin at 154 and San Julian at 131, and San Pedro at 13. The densest rural barangay is Gabao and Gulang-gulang with 11 persons per hectare, and Macawayan at 10. Rural barangays with lowest population density is Cawayan with less than one person per hectare, followed by Cogon, Gumapia, Liang, Mapaso and Tabon-tabon with only 1 person per hectare.