The percentage of the population paying premiums into the national pension system came to 79.6 percent in fiscal 1997, the first drop below 80 percent in 36 years, the Social Insurance Agency said in a report issued Friday.

According to the annual report, the prolonged recession was the main factor behind the decline.

It was also found that 14.1 percent of those covered by the system were by law exempt from paying premiums because they received less income than in the previous year, a case that in many instances resulted from unemployment.