Still, the study’s authors cautioned the projections are preliminary.

Illinois residents finding the exits SPRINGFIELD — The door to Illinois continues to swing outward more often than it does inward.

“We are only at the midpoint of the decade, and a lot of things could change before the next Census is taken in 2020,” Kimball Brace, president of Election Data Services, said in the report. “Having worked with Census data and estimates since the 1970s, it’s important to remember that major events like Katrina and the 2008 recession each changed population growth patterns, and that impacted and changed the next apportionment.”

If population trends continue, 2020 will mark the fifth decennial census in a row in which Illinois has lost representation. In 1980, Illinois lost two districts. It lost another two in 1990 and one each in 2000 and 2010. Today, Illinois has 18 representatives in the House.

The change would cut Illinois’s political clout in Washington, D.C., while also decreasing the number of Electoral College votes the state receives during presidential elections.

'A cost to corruption'

Experts said a number of factors have contributed to Illinois’s population drain.