By 2018, with an estimated 10% annual rate increase, the average family of three would have to make $29,000 more per year for the cheapest Affordable Care Act plan to be deemed "affordable" by the law's definition, according to a recent study by eHealth, a private online health insurance exchange.

Why it matters: President Trump has threatened to "let Obamacare implode" in the face of the failure of several repeal and replace efforts by Republican lawmakers, and these hikes would affect a large portion of the middle and working class of Trump's base. He has also threatened to stop paying the law's cost-sharing subsidies to insurance companies, which would make premiums shoot up even more.

Definition of affordable: When the annual premiums of the cheapest plan under the ACA are more than 8.16% of a household's income, it is considered unaffordable and families can be exempted from the individual mandate.

How the study worked: eHealth reviewed the cheapest 2017 plans available for families of three with two 35-year-old adults and one child from a total of 50 cities, including New York City, Chicago, San Francisco, D.C. and Miami. Of the cities studied, only in Detroit, Albuquerque and Pittsburgh was the plan considered "affordable."