Where could we find data about the number of yearly LP album releases for 1948 to present day?

Where could we find data about the number of yearly LP album releases for
1948 to present day?

Dear Newsgroup reader,

At the moment we* are doing a paper on the diffusion and take-off of
hardware and software.

One of the markets we are interested in is the LP market. We are looking for
data regarding yearly sales of LP-players, and data regarding the number of
new releases (new records/LPs released) in a particular year. Preferably
about the US market from its conception (1948) to the present.

Our question is, do you know of any sources where we can find this data?

With Regards,
Jeroen Binken.

Erasmus University Rotterdam
Faculty of Economics
Department of Marketing and Organization

* (Stefan Stremersch, Assistant Professor of Marketing, Erasmus University
Rotterdam; Gerard Tellis, Jerry & Nancy Neely Chair in American Enterprise
and Professor of Marketing, University of Southern California; Philip Hans
Franses, Professor of Econometrics and Marketing Research, Erasmus
University Rotterdam; and myself, Jeroen Binken, PhD Student, Erasmus
University Rotterdam)