Found this posted earlier last week via Digital Koans:

Digital Project Staff Survey of JPEG 2000 Implementation in Libraries

The data is presented in an xls, that includes all survey questions and comments from those who volunteered information. What I thought was most interesting was that only 60% of respondents (out of 173 total) were using JPEG2000 in any way. The followup question was “if not, why not”, and the general themes include the lack of tools, adoption, and understanding of the format.

For digital preservation, or archival uses, only 20% were making use of the format. There are a lot of very interesting tidbits in this spreadsheet.