How many states have mandatory proficiency tests?

Critics charge that standardized tests became a mandatory curriculum placed into schools without public debate and without any accountability measures of its own. Many feel this ignores basic democratic principles in that control of schools' curricula is removed from local school boards, which are the nominal curricular authority in the U.S. While some maintain that it would be preferable to simply introduce mandatory national curricula, others feel that state mandated standardized testing should stop altogether in order that schools can focus their efforts on instructing their students as they see fit.