CHICAGO — In a report released today, government finance watchdog group the Civic Federation announced its opposition to Gov. Rauner’s latest budget proposal,, saying it  is at least $3.5 billion out of balance.

The report found Rauner’s budget plan “does not fully account for the actual cost of essential state services and is based on projected savings that are unlikely to be realized.”

Those unlikely savings include reducing pension contributions by almost $750 million, largely by deferring payments, as well as cutting employee health insurance costs by $445 million.

An additional $475 million in one-time savings would come from emptying the state’s rainy day fund and the sale of the James R. Thompson Center in Chicago, which requires legislative approval.

If that deficit is not addressed, the Civic Federation estimates the state’s backlog of unpaid bills could reach a new high of $12.8 billion by the end of the next fiscal year.

Because of the FY2016 budget impasse, the backlog of unpaid claims had grown to $2.9 billion by the end of February 2016 and was expected to increase by $200 million per month.

Group health insurance is one of the main areas of government that has not received funding during the budget standoff. However, the costs of the program must be paid eventually due to State law and union contracts, and interest penalties will be paid at the same time.