The following are some figures based on the PISA scores of 2003. The 2003 survey, which focused on mathematics, added a problem solving section. The ideal fifteen-year-old problem solver "can think about the underlying relationships in a problem, solve it systematically, check their work and communicate their skills" (OECD, 2004, p. 3). In the 2003 survey, 41 countries participated.
These figures illustrate the scores for countries relevant to my research: the Nordic countries of Finland, Sweden, Denmark, Norway, and Iceland; South Korea, Japan, Germany, the United States, and the United Kingdom.
You can see the the PISA scores and distributions for all participating countries in the Relevant Links section listed on the right.