The CCSSO release of "State Indicators of Science and Math Education" is the tool that most education materials publishers use to evaluate the market share of content areas, such as the number of students taking biology, and thus the market for education materials.
The Table of Contents includes: Introduction and Table of Contents Ch. 1: Indicators of Student Achievement in Math and Science Ch. 2: Indicators of Math and Science Curriculum Ch. 3: Indicators of Teacher Preparation and Supply Ch. 4: Indicators of Context and Conditions for Teaching Appendices A: Data Sources and Computations B: Directory of State Course Titles by Reporting Categories; Detailed State-Level Data