| Year | Dollar Level (in billions) | Authorization |
|---|---|---|
| 1992 | 0.86 | ISTEA |
| 1993 | 1.03 | ISTEA |
| 1994 | 1.03 | ISTEA |
| 1995 | 1.03 | ISTEA |
| 1996 | 1.03 | ISTEA |
| 1997 | 1.03 | ISTEA |
| 1998 | 1.19 | TEA-21 |
| 1999 | 1.35 | TEA-21 |
| 2000 | 1.36 | TEA-21 |
| 2001 | 1.38 | TEA-21 |
| 2002 | 1.41 | TEA-21 |
| 2003 | 1.43 | TEA-21 |
| 2004 | 1.43 | TEA-21 |
| 2005 | 1.67 | SAFETEA-LU |
| 2006 | 1.69 | SAFETEA-LU |
| 2007 | 1.72 | SAFETEA-LU |
| 2008 | 1.75 | SAFETEA-LU |
| 2009 | 1.78 | SAFETEA-LU |
