The following table gives the percentage distribution of the 1992 U.S. labor force by educational attainment: Educational Attainment Percentage of Workers Less than a high school diploma 12.4 High school graduates 35.7 Some college but no degree 18.0 Associate degree 7.4 Bachelor's degree 17.2 Master's degree 6.5 Professional or doctoral degree 2.8 A recent sample of 1000 workers showed that 116 have less than a high school diploma, 363 are high school graduates with no college, 164 have some college but no degree, 71 possess an associate degree, 187 hold bachelor's degree, and 61 have a master's degree, and 38 possess a professional or doctoral degree. Test at 1% significance level if the percentage distribution of the U.S. labor force by education attainment has changed since 1992