Californians who buy their health insurance through the state’s exchange will have more sticker shock next year when their rates increase by an average 12.5 percent statewide.

But consumers in most Bay Area counties will see much smaller increases — from an average 4.3 percent to 8.3 percent — according to data released Tuesday by Covered California, the state-run “Obamacare” exchange that allows individuals and small businesses to purchase health insurance at federally subsidized rates.

What’s more, said exchange CEO Peter Lee, rates across the state would have dropped about another 3 percent if the 11 insurers offering plans on the exchange weren’t so worried about the Trump administration’s potential to undermine the Affordable Care Act.

“We were hopeful that this year we would be back to normal,” Lee told reporters during a Tuesday morning press call. But “uncertainty in Washington is affecting consumers today.”

Lee also noted that while all…