Percentage is larger than the 2015 percentage at the .05 level of statistical significance.

Percentage is smaller than the 2015 percentage at the .05 level of statistical significance.

NOTE: U.S. trend tables show data for all available years. All percentages reported as larger or smaller than the 2015 percentages are different at the .05 level of statistical significance. Standard error is abbreviated as s.e. The United States met guidelines for sample participation only after replacement schools were included in 1995, 2007, and 2015. The United States nearly satisfied guidelines for sample participation rates after replacement schools were included in 2003. The United States' National Defined Population covered 90 to 95 percent of the National Target Population in 2007 and 2011.

SOURCE: International Association for the Evaluation of Educational Achievement (IEA), Trends in International Mathematics and Science Study (TIMSS), 1995, 1999, 2003, 2007, 2011, and 2015.