(CNN) - Six million people are expected to pay a penalty for not having health insurance in 2016.
That's a big jump from two years ago when the estimate was four million.
Under the Affordable Care Act, sometimes referred to as "Obamacare," Americans must be insured starting in 2014. If not, they'll have to pay a penalty.
The estimate of six million is from the Congressional Budget office and Joint Taxation Office.
Why the increase? The groups blame the weak economy. With a high unemployment rate and lower salaries, not everyone will be getting coverage from an employer and they might not be able to afford buying it on their own.
New legislation is also a factor. This summer's Supreme Court decision gives states the option to expand Medicaid only if they want to. That could leave some of the poorest Americans uninsured.
So just how much is the penalty? In 2014, it will be no more than one percent of income, or $285 per family, whichever is greater.
That penalty will rise, though. By 2016, it jumps to 2.5 percent of income or about $2,000 per family.
Still most of the uninsured won't have to pay the fee. Those with very low incomes who don't have to file federal tax returns will be exempt. So will members of certain religious groups.