For example, data from the PISA study administered in 2015 reveal that 76% of native-born students of native-born parents in Sweden attained at least proficiency level 2 in the three PISA core domains -mathematics, reading and science. By contrast, only 49% of immigrant students (either first- or second-generation) did so, a statistically significant difference of 27 percentage points. This difference was greater than the OECD average difference of 18 percentage points.