More than 7 million people paid Obamacare penalties this year, but experts say that figure is bound to decline by a million people or two next year as the penalties skyrocket.

Preliminary figures from the IRS show that about 7.5 million people paid up to $1.5 billion and another 12 million received a low-income exemption to Obamacare's individual mandate penalty. The law requires a taxpayer to pay a penalty of $95 or 1 percent of yearly income, whatever is higher, if he doesn't have insurance.

But since the mandate penalty increases next year, and because coverage is increasing, experts peg next year's number to be about 5 to 6 million people paying the fine.

Low-income taxpayers can get an exemption to the penalty, and about 12 million taxpayers did just that, according to a letter from IRS Commissioner John Koskinen to members of Congress.

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The individual mandate is one of the most controversial parts of Obamacare, but also a key driver in getting people to sign up for the law. But about 1 million more people than estimated by the administration paid the penalty.

The total number is bound to decline, however, starting in 2016, said Matthew Buettgens, senior research associate with the Urban Institute.

He said more people are getting coverage this year than in 2014.

A Gallup poll from April showed that the uninsured rate fell to 11.5 percent in the second quarter of this year, down from 11.9 percent in the first quarter. Gallup said as a whole the uninsured rate has dropped nearly six points since the end of 2013, when the first open enrollment period ended.

"It is highly likely that the number of people paying the penalties will be lower because more people are getting covered," Buettgens told the Washington Examiner on Tuesday.

He estimated the number of people paying the penalty in 2016 will be more like 5 to 6 million.

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Another reason could be the drastically higher penalty for 2015. Taxpayers without insurance would have to fork over 2 percent of yearly income or $325 per person.

"As the penalty increases and awareness grows in the next few years, a growing share of the remaining uninsured will probably choose to get covered rather than take the hit," said Katherine Hempstead, director of health insurance coverage for the Robert Wood Johnson Foundation.

All of the money from the penalty goes to the Treasury Department.

This year about 11 million people signed up or re-enrolled in Obamacare, an increase from the 8 million who signed up in 2014.

Buettgens wasn't sure if the penalty was the driving force behind the boost from 2015 to 2014, but said that it could have been a factor.