Era
1996
20
1994
16
1993-2001
13
1993
12
1995
12
1998
12
1997
11
1993-
8
1981-2001
7
Since 1993
7
2007
6
2005
5
2006
5
2004
4
2001-2009
3
2001-2009-
3
2003
3
2008
3
2009
3
1981-1993
2
Since 1981
2
1971-
1
1971-1981
1
1981 - 2001
1
1981-
1
1992
1
1997-1998
1
1999
1
2000-2099
1
2001-2011
1
2012
1
21st century
1
Appropriations and expenditures, 1994-1998
1
Appropriations and expenditures, 1996
1
Appropriations and expenditures, 1997
1
Appropriations and expenditures, 1997-1998
1
Since 1971
1