- The age group-based HBsAg (+) ratio was 14.8% among patients <20 years old, 17.1% among patients of 20 - 29 years old, 19.5% among patients of 30 - 39 years old, 23.8% among patients of 40 - 49 years old and 7.9% among patients of 50 - 59 years old.