Economic Assumptions under the Three Alternatives

(Author's note. In February 2006, the Social Security Administration took down the HTML versions of the 1997 to 2000 Reports. Those links will no longer work. The Reports are still available in PDF form and it is possible that we will get them mirrored somewhere else on the web, at which point I will fix the links.)
The tables linked to here show the economic projections under all three alternatives from the 1996 Report to the 2005 Report. Note how the numbers projected for the out years (after 2010) change over time. Why does the crystal ball get increasingly cloudy?

2005 Report
2004 Report
2003 Report
2002 Report
2001 Report
2000 Report
1999 Report
1998 Report
1997 Report
1996 Report