FIGURE 8.7 Changes in IQ score over time among Danish adults with relatively low IQ scores (10th percentile) and relatively high IQ scores (90th percentile) As these data illustrate, IQ scores have improved considerably over the years among Danes near the bottom of the distribution but have remained virtually constant among people near the top. In the United States, increases have been more uniform throughout the IQ distribution. (Adapted from Geary et al., 2005)