Concomitantly, the disposable income of this group declined from 2.5 times the national average in 1993 to just 1.8 in 2009 (Rodrigues et al, 2012). Successive governments have made a determined effort to improve the general level of education of the Portuguese population, and although such improvements always take time to show up in the data, there are some encouraging results. Between 2001 and 2011 the proportion of people aged 25-34 who attained at least upper secondary education rose from 32% to 56%, and the proportion of people with tertiary education almost doubled. In Portugal, the association between students' socio-economic background and their performance at school is more pronounced than on average in the OECD, and much of this relation lies at the school level (Figure 14).