This can be explained by one of the biggest increases in first-time graduation rates at the upper secondary level in Europe - from 41% to 86% between 2005 and 2013. Attainment of below upper secondary level is rare in Poland - no adults have lower secondary education as their highest level of attainment, although 9% have only completed primary education, compared to an OECD average of 7%. Poland also has an above-average proportion of adults whose highest level of attainment is upper secondary vocational programmes: out of the 64% of adults whose highest level of education is upper secondary or postsecondary non-tertiary education, 87% were enrolled in vocational education compared to an OECD average of 66%.