URBANA — The University of Illinois flash index fell in October — the first monthly decline in 17 months — but the economist who compiles it says he still doesn't expect a double-dip recession.

The index — based on tax receipts from Illinois corporate income, personal income and retail sales — dropped from 98.8 in September to 98.3 in October.

In the 17 months before that, the index had steadily climbed from 90.6 in May 2010 to 98.8 in September 2011.

The 100 mark is considered the division between economic expansion and contraction, with values higher than 100 suggesting expansion and values lower than 100 suggesting contraction.

But economist J. Fred Giertz of the UI's Institute of Government and Public Affairs said the flash index didn't fall as far in October as it rose in September.

The index still remains above the 97.8 level that prevailed from June to August, he said.

"The two-month result suggests that the economy is not likely headed for a double-dip recession that was a concern nationally last month," he said.

Giertz noted that the Illinois unemployment rate was 10 percent in September, well above the national rate.

That's a change from a year earlier when the state's rate was below the national rate, he said.

During October, individual income tax and corporate tax receipts were down compared with those of October 2010, when adjusted for inflation. Sales tax receipts, however, were up.

The calculations were made after adjusting for the individual and corporate income tax rate increases earlier this year.