Fewer parents in Maine chose not to vaccinate their kindergarten-age children last year for religious or philosophical reasons, although the state’s vaccination opt-out rate remains in the upper tier nationally. During the 2014-15 school year, an estimated 4.4 percent of children enrolled in kindergarten across the state did not receive vaccinations for such contagious diseases as measles or whooping cough because parents chose to exempt them, according to school survey data released Friday by the U.S.