WASHINGTON – One in eight people earning at least $1 million annually were audited by the Internal Revenue Service last year, making them far likelier to be examined than those making below $200,000, according to IRS data released Thursday.

Just 1 in 100 individuals earning less than $200,000 had their income tax returns examined, the IRS said.

The 12 percent of millionaire earners audited in 2010 was appreciably higher than the 8 percent who were audited in 2009. IRS officials said the high ratio was part of an effort to demonstrate that tax laws are applied fairly.

“That has been something we’ve concentrated on to assure that there’s equity in the system, to assure that those at the lower end of the spectrum know that those at the higher end of the spectrum are subject to the same rules and enforcement as everyone else,” Steven Miller, deputy IRS commissioner for services and enforcement, said in an interview.

The IRS said its overall effort to collect all taxes owed netted $55 billion. That is nearly $3 billion less than the previous year, which Miller attributed to a falloff in estate taxes and corporations writing off their losses.

All together, the IRS audited nearly 1.6 million of the 141 million individual income tax returns that were filed. In 2010 — the most recent year available — more than eight in 10 individuals audited ended up paying additional taxes.

The agency collected a total of $2.3 trillion in revenue last year from individuals and businesses.