Yeah, that's sustainable. From California Healthline:
Molina Healthcare has the highest rate increase for 2018, at 44.7 percent. Valley Health Plan is lowest at 9.8 percent.
Blue Shield of California, the largest insurer in Covered California by enrollment, fell in between with an average hike of 22.8 percent. HMO giant Kaiser Permanente will charge 11.6 percent more on average next year. (Kaiser Health News, which produces California Healthline, is not affiliated with Kaiser Permanente.)