I see separate columns for current and constant dollars. Your numbers are from the current column.
Here are the numbers from the constant column:
1998: 2,040.9
1999: 2,136.4
2000. 2,310.0
2001: 2,215.3
2002: 2,028.6
2003: 1,901.1
2004: 1,949.5
2005: 2,153.6
2006: 2,324.1
2007: 2,414.0
2008: 2,288.1
2009: 1,899.0
2010: 1,927.9
2011: 1,998.7
Furthermore, the very own website you've chosen to cite says the following:
"The Bush tax cuts contributed, along with underlying economic conditions, to a historic decline in federal tax revenue. In 2000 total federal tax revenue was as high in proportion to the U.S. economy as it had ever been. By 2004 federal tax revenue in proportion to the economy had fallen to its lowest level in almost fifty years." link