| 1976 | 1977 | 1978 | 1979 | 1980 | 1981 | 1982 | 1983 | 1984 | 1985 | 1986 | 1987 | 1988 | 1989 | 1990 | 1991 | 1992 | 1993 | 1994 | 1995 | 1996 | 1997 | 1998 | 1999 | 2000 | 2001 | 2002 | 2003 | 2004 | 2005 | 2006 | 2007 | 2008 | 2009 | 2010 | 2011 | 2012 | 2013 | 2014 | 2015 | 2016 | 2017 | 2018 | 2019 | 2020 | 2019 - 2020 Change |
2015 - 2020 Change |
Proportional Change |
Peak year - 2020 Change |
Proportional Change |
Low year - 2020 Change |
Proportional Change |
||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Lifetime | 8th Grade | . | . | . | . | . | . | . | . | . | . | . | . | . | . | . | 1.9 | 1.7 | 1.6 | 2.0 | 2.0 | 1.8 | 1.8 | 2.3 | 2.7 | 3.0 | 2.8 | 2.5 | 2.5 | 1.9 | 1.7 | 1.6 | 1.5 | 1.4 | 1.3 | 1.1 | 1.2 | 1.2 | 1.1 | 1.0 | 1.0 | 0.9 | 1.1 | 1.1 | 1.5 | 2.0 | | | 0.5 | | | 1.0* | 102.5 | | | -1.0* | -32.5 | | | 1.1** | 123.7 |
| 10th Grade | . | . | . | . | . | . | . | . | . | . | . | . | . | . | . | 1.8 | 1.7 | 1.7 | 1.8 | 2.0 | 1.8 | 2.0 | 2.0 | 2.7 | 3.5 | 3.4 | 3.5 | 3.0 | 2.4 | 2.0 | 1.8 | 1.8 | 1.4 | 1.3 | 1.6 | 1.4 | 1.3 | 1.3 | 1.4 | 1.2 | 1.3 | 1.1 | 1.2 | 1.6 | 1.7 | | | 0.1 | | | 0.4 | 35.3 | | | -1.8*** | -52.2 | | | 0.6 | 53.5 | |
| 12th Grade | . | . | . | . | . | . | . | . | . | . | . | . | . | 3.0 | 2.9 | 2.1 | 2.1 | 2.0 | 2.4 | 2.3 | 1.9 | 2.4 | 2.7 | 2.9 | 2.5 | 3.7 | 4.0 | 3.5 | 3.4 | 2.6 | 2.7 | 2.2 | 2.2 | 2.2 | 2.0 | 1.8 | 1.8 | 2.1 | 1.9 | 2.3 | 1.6 | 1.6 | 1.6 | 1.6 | 2.0 | | | 0.5 | | | -0.3 | -12.7 | | | -1.9** | -48.6 | | | 0.5 | 30.2 | |
| Last 12 Months | 8th Grade | . | . | . | . | . | . | . | . | . | . | . | . | . | . | . | 1.0 | 1.1 | 0.9 | 1.2 | 1.0 | 0.9 | 1.0 | 1.2 | 1.7 | 1.7 | 1.6 | 1.5 | 1.4 | 1.1 | 1.1 | 0.9 | 0.8 | 0.9 | 0.8 | 0.5 | 0.7 | 0.6 | 0.6 | 0.6 | 0.5 | 0.5 | 0.6 | 0.6 | 0.8 | 1.1 | | | 0.4 | | | 0.6 | 114.6 | | | -0.5 | -32.2 | | | 0.6 | 114.6 |
| 10th Grade | . | . | . | . | . | . | . | . | . | . | . | . | . | . | . | 1.1 | 1.1 | 1.0 | 1.1 | 1.2 | 1.2 | 1.2 | 1.2 | 1.7 | 2.2 | 2.1 | 2.2 | 1.7 | 1.5 | 1.3 | 1.2 | 1.1 | 0.9 | 0.8 | 1.0 | 0.9 | 0.8 | 0.8 | 0.8 | 0.7 | 0.7 | 0.7 | 0.6 | 0.8 | 0.9 | | | 0.1 | | | 0.2 | 21.1 | | | -1.3*** | -58.9 | | | 0.3 | 41.3 | |
| 12th Grade | . | . | . | . | . | . | . | . | . | . | . | . | . | 1.9 | 1.7 | 1.4 | 1.1 | 1.2 | 1.3 | 1.5 | 1.4 | 1.4 | 1.7 | 1.8 | 1.7 | 2.4 | 2.5 | 2.1 | 2.5 | 1.5 | 1.8 | 1.4 | 1.5 | 1.5 | 1.5 | 1.2 | 1.3 | 1.5 | 1.5 | 1.7 | 1.0 | 1.1 | 1.1 | 1.1 | 1.2 | | | 0.1 | | | -0.5 | -26.8 | | | -1.3** | -51.0 | | | 0.2 | 20.7 | |
| Last 30 Days | 8th Grade | . | . | . | . | . | . | . | . | . | . | . | . | . | . | . | 0.4 | 0.5 | 0.5 | 0.5 | 0.6 | 0.4 | 0.5 | 0.5 | 0.7 | 0.8 | 0.7 | 0.8 | 0.7 | 0.5 | 0.5 | 0.5 | 0.4 | 0.5 | 0.4 | 0.3 | 0.4 | 0.3 | 0.3 | 0.2 | 0.3 | 0.3 | 0.3 | 0.3 | 0.3 | 0.3 | | | -0.0 | | | 0.1 | 21.2 | | | -0.5** | -59.4 | | | 0.1 | 40.1 |
| 10th Grade | . | . | . | . | . | . | . | . | . | . | . | . | . | . | . | 0.6 | 0.6 | 0.5 | 0.6 | 0.6 | 0.5 | 0.7 | 0.6 | 0.9 | 1.0 | 0.9 | 1.0 | 0.8 | 0.8 | 0.6 | 0.6 | 0.5 | 0.5 | 0.5 | 0.5 | 0.5 | 0.4 | 0.4 | 0.4 | 0.4 | 0.3 | 0.3 | 0.4 | 0.4 | 0.5 | | | 0.0 | | | 0.1 | 22.0 | | | -0.6** | -54.8 | | | 0.2 | 77.7 | |
| 12th Grade | . | . | . | . | . | . | . | . | . | . | . | . | . | 0.8 | 1.0 | 0.8 | 0.6 | 0.7 | 0.9 | 0.7 | 0.7 | 1.0 | 1.1 | 0.9 | 0.8 | 1.3 | 1.4 | 1.3 | 1.6 | 0.9 | 1.1 | 1.0 | 1.0 | 1.0 | 1.1 | 0.7 | 0.9 | 1.0 | 0.9 | 1.0 | 0.7 | 0.8 | 0.8 | 0.8 | 1.2 | | | 0.4 | | | 0.1 | 14.7 | | | -0.4 | -25.9 | | | 0.5 | 65.1 | |