Contents: Executive Summary --- Introduction --- Estimated Participation Rates for FY 2009 --- Recent Trends in Participation Rates --- Participation Rates for Subgroups in FY 2009 --- Trends in Participation for Subgroups --- Benefit Receipt Rates in FY 2009 --- Factors Associated with Change in Participation Rates --- Methodology --- References --- Appendix A: Selected Individual and Household Participation Rates and Benefit Receipt in FY 2009 --- Appendix B: Detailed Participation Rates in FY 2009 --- Appendix C: Change in Individual SNAP Participation Rates, 1988 to 2009 --- Appendix D: Methodology --- Appendix E: Sampling Error of Participation Rate Estimates --- Appendix F: Economic and Policy Influences on SNAP --- Appendix G: Changes in the CPS ASEC Over Time --- Appendix H: SNAP Eligibility Parameters