About 7.5 million Americans paid an average penalty of $200 for not having health insurance in 2014 — the first year most Americans were required to have coverage under the Affordable Care Act, the Internal Revenue Service said Tuesday.

The government had estimated in January that from 3 million to 6 million households would have to pay a penalty: 1% of their annual income or $95 per adult in 2014, whichever is greater.

By contrast, 76% of taxpayers checked a box indicating they had insurance coverage all year.

Final figures for the tax year aren't available. The IRS has so far processed about 135 million of the estimated 150 million returns expected.

So far, the IRS said it has collected $1.5 billion from the individual mandate penalty included in the health law.

Some 12 million people avoided the penalty because they received exemptions. They included those whose incomes were too low and Native Americans.

About 300,000 taxpayers who paid a penalty should have claimed an exemption but did not, the government said. The agency is sending letters to these taxpayers telling them they generally have three years to file an amended tax return to claim the funds.

More than 5 million taxpayers skipped over the health insurance box. They did not indicate they had coverage, claim an exemption, or pay a penalty.

"We are analyzing these cases to determine their status," the government said.

Separately, the IRS reported Tuesday that 2.7 million taxpayers claimed their Obamacare subsidies on their tax returns, instead of having it paid in advance directly to insurers. They received an average subsidy of $3,400.

About 1.6 million people had to pay money back to the government because their actual income was higher than projected when they applied for the subsidy. The average amount repaid was about $800.