Composers in the British National Corpus

I have recently come across this intriguing graphical representation of the frequency of words in the British National Corpus, a corpus of spoken and written British English dating from the early 1990’s. As it includes proper names, I tried various names of composers (the number is the place in the frequency table, low numbers signifying high frequency):

Mozart 6234
Bach 11830
Beethoven 11942
Haydn 20025
Stravinsky 21886
Tchaikovsky 22807
Elgar 23091
Purcell 24229
Schubert 24638
Mahler 26589
Shostakovich 29140
Debussy 29336
Schoenberg 30784
Puccini 41577
Tippett 43223
Webern 47165
Messiaen 53446

What I don’t know is the absolute frequencies and I wonder whether at the less frequent end differences of thousands of places may conceal little or no difference in frequency. I left out some names which could turn up frequently as common nouns or other people’s names (e.g. Strauss (17539), Gibbons (20388), Wagner (11505, though I bet most of these are the composer)). Sometimes something named after the composer may inflate their count; I suspect the Tallis Scholars have done this for Tallis (12911) though the Monteverdi Choir has not boosted Monteverdi (34755) very much, and maybe the Purcell School has done it for Purcell.