Here are some resources for understanding the economics of symphony orchestras:
An article by William Baumol, the pre-eminent cultural economist, about the economic structures and issues for education, health care and the performing arts
An article on the economics of symphony orchestras and their historical trends
An excellent and comprehensive introduction to the topic- well worth the $200, or an inter-library loan. This link has several chapters posted on a rotating basis.
U.S. Bureau of Economic Analysis
U.S. Bureau of Labor Statistics: Occupational Employment Statistics