A 2015 estimate by the United States Central Intelligence Agency puts the literacy rate in Russia at 99.7% (99.7% for men, 99.6% for women). According to a 2016 OECD estimate, 54% of Russia's adults (25- to 64-year-olds) have attained a tertiary education, giving Russia the second-highest attainment of tertiary education among 35 OECD member-countries. 47.7% have completed secondary education (the full 11-year course); 26.5% have completed middle school (9 years) and 8.1% have elementary education (at least 4 years). Highest rates of tertiary education (24.7%) are recorded among women aged 35 to 39 years (compared to 19.5% for men of the same age bracket).