Low-income families' ability to sustain employment while ensuring the care and safety of their young children is profoundly affected by federal policies regarding access to subsidies and programs, such as Head Start. The current structure of these policies evolved during the decades following the 1990 enactment of the Child Care and Development Block Grant -- a period that also witnessed expansion of the Head Start program and growth of state pre-K programs. Using data from two nationally representative surveys of child care providers conducted in 1990 and 2012, this paper examines trends in the supply, sponsorship, and funding structure of publicly-funded child care centers during this period of active policymaking in early care and education. These changes include major expansion in the number and share of child care centers receiving public funds, as well as in the number of children enrolled in these centers; relatively more rapid growth among for-profit vs. non-profit centers in the publicly-funded sector, but consistency in that the major share of publicly-funded centers remained non-profit; and substantial growth in publicly-funded centers receiving vouchers as a primary funding mechanism. These trends carry the potential to enhance the reach of quality improvement efforts tagged to public funds and may have increased low-income families' choice of centers with differing hours, in a range of locations, that serve a wider age range of children, as well as children supported with differing funding sources. Whether the growing supply of publicly-funded centers has actually kept pace with demand, let alone enhanced access of low-income families to care that supports their children's development, are critical, next-stage questions to address. (author abstract)