I did the newsletter for my quilt guild last year & found the following information on quilting. In 2000 Quilter's Newletter had a survey of 2500 quilters in U.S.
They found Total U.S. Quilting Industry Value
• $118.02 average annual household expenditure, a 17.3% increase over 1997
• $1,836,456,111 total annual U.S. quilting expenditure ($1.836 Billion dollars)
• Value of U.S. quilting industry has increased 51.6% since 1997**
I don't know if there is a more recent survey, but I am sure expenditures are down because of the economy