In 2009, high school graduates earned an average of 3 credits more than in 1990. In 2009, graduates earned 27.2 credits, up from 23.6 in 1990. Each credit represents 120 hours of classroom instruction.
Trend in average credits earned: 1990-2009
| 1990 | 
1994 | 
1998 | 
2000 | 
2005 | 
2009 | 
| Average credits earned | 
Standard error | 
Average credits earned | 
Standard error | 
Average credits earned | 
Standard error | 
Average credits earned | 
Standard error | 
Average credits earned | 
Standard error | 
Average credits earned | 
Standard error | 
Total credits 
earned | 
23.6 | 
* | 
(0.12) | 
24.3 | 
* | 
(0.14) | 
25.3 | 
* | 
(0.17) | 
26.2 | 
* | 
(0.20) | 
26.8 | 
* | 
(0.09) | 
27.2 | 
  | 
(0.10) | 
 * Significantly different (p<.05) from 2009.
SOURCE: U.S. Department of Education, Institute of Education Sciences, National Center for Education Statistics, High School Transcript Study (HSTS), various years, 1990-2009.