So what happened? George W Bush happened.
"In the absence of significant legislative changes and assuming that the economy follows the path described in this report, the Congressional Budget Office (CBO) projects that the total surplus will reach $281 billion in 2001. Such surpluses are projected to rise in the future, approaching $889 billion in 2011 and accumulating to $5.6 trillion over the 2002-2011 period. That total is about $1 trillion higher than the cumulative surplus projected for 2001 through 2010 in CBO's July 2000 report. About $600 billion of the $1 trillion increase is due simply to shifting the 10-year horizon out one year, to 2011, and dropping 2001 from the total. The remaining $441 billion results mostly from changes in the economic forecast, which are offset in part by the cost of legislation enacted since CBO's previous report.
Perhaps more important to some policymakers, the on-budget surplus (which excludes the spending and revenues of Social Security and the Postal Service) is anticipated to equal $125 billion in 2001--a nearly $40 billion increase from its level in 2000. The on-budget surplus will continue growing over the 10-year period, CBO projects, exceeding $550 billion in 2011 and totaling over $3.1 trillion between 2002 and 2011.
The growth of economic activity--as measured by real (inflation-adjusted) gross domestic product (GDP)--is likely to slow from its rapid pace of recent years to about 2.4 percent this calendar year. Spending by consumers and investment by businesses slowed late last year in response to the rise in interest rates during 1999 and early 2000 and to reduced expectations about future business conditions. Although the Federal Reserve Board in early January responded to the slower growth by lowering the federal funds rate, spending by consumers and businesses is likely to remain weak in the near term. However, lower interest rates this year will set the stage for moderately faster growth of spending next year. Thus, CBO forecasts that economic growth will climb to about 3.4 percent in calendar year 2002.
How is it, then, that budget projections are getting better when the economy seems to be getting worse? There are two main answers to that question. First of all, the dip in the economy is expected to be short-lived. CBO forecasts that economic growth will pick up again by the middle of 2001. Over the 2002-2011 period, CBO anticipates that growth of real GDP will average a little over 3 percent per year--about 0.3 percentage points above its 10-year projection in July. That increase reflects a change in CBO's method of calculating the contribution of capital to growth, revised data showing greater investment for the past three years, and higher projected levels of investment. Changes due to higher projections of GDP and other economic factors boost projected revenues by $802 billion from 2001 through 2010.
Second, recent economic conditions and actions by the Federal Reserve have led CBO to significantly reduce its forecast of interest rates in 2001 and 2002 (but that factor is not nearly as large as the first). Lower near-term interest rates and reduced levels of projected debt across the 10-year period (due to higher projected surpluses) combine to increase estimates of the surplus by about $140 billion from 2001 through 2010."
http://www.cbo.gov/doc.cfm?index=2727&type=0&sequence=1