I'm reading around 10-25% (more for California) for commercial plans, but there are so many factors it would be a wild guess. So many variables that would come into play: type of plan, type and level of benefits, specific costs incurred the past year and in the plan's geographical area, etc.

A person who is Medicare eligible has good news though; Medicare Advantage plan premiums are expected to drop slightly due to an expected 5% increase in enrollment. Premiums were expected to increase, but will drop 1%.