When Massachusetts passed its landmark health insurance law under Gov. Mitt Romney in 2006, no one claimed the state would get to zero — as in 0 percent of residents who are uninsured. But numbers out this week suggest Massachusetts is very close. Between December 2013 and March of this year, the number of Massachusetts residents signed up for health coverage increased by more than 215,000. If that number holds true over time, it will mean the percentage of Massachusetts residents who lack coverage has dropped to less than 1 percent. "We're thrilled that we are getting this close to universal health care access," said the Rev. Burns Stanfield, president of the Greater Boston Interfaith Organization.