Mitt Romney said one reason he doesn't want to release more of his tax returns is because it would show how much money he has given to the Mormon Church.

"Our church doesn’t publish how much people have given," Romney said in an upcoming interview with Parade magazine. The Salt Lake Tribune previously reported on the interview. "This is done entirely privately. One of the downsides of releasing one’s financial information is that this is now all public, but we had never intended our contributions to be known. It’s a very personal thing between ourselves and our commitment to our God and to our church."

Romney has released his 2010 tax returns and an estimate of his 2011 returns. He said he plans to release the full 2011 records as soon as they are fully available. But Democrats have strongly criticized Romney for not releasing more of his tax records, and suggested that his refusal to do so is a likely indication he's hiding something.

Recently, Romney said he reviewed his tax returns and paid a federal income tax of 13 percent each year over a period of 10 years. He did not produce any documents as evidence.