Distribution Quandary

Does anyone know a surefire way of finding out if a movie was released theatrically in a given calendar year in the US? If so please share. I find that IMDB has too many errors to trust in this regard (and also: absolutely no specifics as to the where ...so it might be a festival rather than a regular release). Sites like movieweb and coming soon and others do seem a little vague too, particularly when it comes to indies or foreign films with tiny distributors.