In 2017, the IRS audited 1 of every 160 individual tax returns, the lowest percentage since 2002, and the sixth straight year of declines. Overall audit probabilities peaked in 2010 at 1 in 90. For millionaires, the audit probabilities are 1 in 23, down from 1 in 8 in 2010. And remember, for you late filers, the IRS only takes checks for up to $99,999,999.99; what a pain!