Music Ngram Viewer
http://www.peachnote.com/

When you enter melodies into the Music Ngram Viewer, it displays a graph showing how those melodies have occurred in a corpus of scores (e.g., “IMSLP”) over the years. The data for Music Ngram Viewer comes from around 1,600,000 OMR’ed sheets from some 160 thousand scores from the Petrucci Music Library, the Library of Congress and the Duke University Library. They contain almost 370 million notes. The scores are currently still being recognized. We will update this corpus as the digitization continues.
Currently the database contains ngrams up to the length 15, or melodies of up to sixteen notes or chords. This makes roughly 360 million melody-year pairs. You can get the list of scores containing the given melody. Time periods are chosen so that the melody occurs roughly the same number of times in each of them. For each period you can view up to 88 scores. This will be added to the tools section of Research Resources Subject Tracer™ Information Blog.