The number of smokers nationwide has fallen below 20 percent of the population for the first time on record, a survey showed Tuesday, giving a boost to the health ministry's proposal to ban smoking in enclosed public spaces.

In the government survey of people aged 20 or older in 2016, 19.8 percent of respondents said they smoke, down 1.8 percentage points from 2013, with the downward trend observed in most age groups for both genders.

The percentage of people who said they smoke every day declined in both genders — a 2.4 point drop for males at 29.1 percent and a 0.9 point fall for females at 8.6 percent. Among women, 86.2 percent said they do not smoke.

The figure for male smokers in their 20s, including those who smoke occasionally, marked the largest drop of 5.4 points from 2013 at 31.1 percent, compared with 55.6 percent in 2001.

By age group, male smokers in their 30s saw the highest rate of 39.9 percent while women in their 80s and above have the lowest at 1.7 percent.

The Ministry of Health, Labor and Welfare has been promoting a bill that would strengthen measures for combating secondhand smoke as the country prepares to welcome more foreign visitors ahead of the 2020 Tokyo Olympics.