Every year, the IRS says it faces an estimated 458-billion dollar tax gap. That’s income taxes that are owed, but not paid. The IRS said it manages to recapture about 52-billion dollars a year through enforcement efforts like tax audits. Most Americans do pay up every year… Voluntary compliance is at 82%. The IRS says the short-fall comes from underreporting, under-repayment and that 18% who just don’t pay.