One last pair of charts, showing the impact of recessions on tax data, via the Rockefeller Institute of Government. These two shows the impact of recessions on general tax receipts, and on retail sales.
In both charts, the current contraction is the worst on record for the time periods (1973, 1964 forward)
Retail Sales: 5 Recessions
State Tax Revenues (1964- 2009)
State Tax Revenues Show Record Drop, For Second Consecutive Quarter
Lucy Dadayan and Donald J. Boyd
The Nelson A. Rockefeller Institute of Government