A slight correction - premiums went up greatly for less than 10% of enrollees, according to NYTimes analysis.    https://www.nytimes.com/interactive/2017/03/09/us/politics/who-is-really-affected-by-rising-obamacare-premiums.html

This analysis found that only 3% of enrollees had large premium increases.

Obamacare is (was) in no danger of collapsing. RUCA (Republican Unaffordable Care Act) on the other hand, is unsustainable. As envisioned, everyone who gained coverage with the ACA would lose it, and millions more. Republicans are playing a dirty trick on American working families.