HIV/AIDS statistics for Philadelphia are collected by the AIDS Activities Coordinating Office (AACO). AACO’s statistics page contains:
For Pennsylvania statistics, including statewide reports, regional reports, and specialized data requests, see the PA Department of Health HIV/AIDS Annual Summary & Other Reports and its Integrated Epidemiologic Profile of HIV/AIDS in Pennsylvania.
For more Pennsylvania statistics (with a particular emphasis on HIV/AIDS funding), see the Kaiser Family Foundation’s State Health Facts webpage on PA and HIV. The State Health Facts page also allows you to compare PA to other states and to find information on other health issues.
For US-wide statistics, see the U.S. Center for Disease Control and Prevention (CDC) website on HIV/AIDS Statistics and Surveillance.
You can also make data requests from the CDC, at their Contact CDC page.
For historical study of the epidemic, see Past Issues back to 1982 of the CDC Surveillance Report.
The Kaiser Family Foundation also has lots of good statistical analysis at their HIV/AIDS in the US webpage. There isn’t one single statistics page, but if you use their “sort” tool, at the bottom of the page, you can sort by Document Type: Charts & Data and Subtopic: HIV/AIDS in the US.
The Joint United Nations Programme on HIV/AIDS, UNAIDS, has a webpage on HIV Data with:
The World Health Organization (WHO) has a page of Data and Statistics. Be aware that many reports and data sets here are identical to those of UNAIDS linked above, as WHO is a co-sponsor of UNAIDS.
The U.S. Census Bureau has its own webpage of Global HIV/AIDS Surveillance. This includes a link to the Census Bureau’s HIV/AIDS Surveillance Database, which includes maps, summary tables, and the option to generate custom reports.
The University of California, San Francisco’s HIV InSite has a page on the epidemic by Counties and Regions. The basic data is drawn from the UNAIDS report linked above, but each page is also filled with links to reports, organizations, and other resources on that county or region.
For U.S. statistics by age, race, and transmission category, see the Center for Disease Control and Prevention (CDC) webpage on Basic Statistics.
For more detailed reports on different populations and risk behaviors, see the CDC’s Surveillance Factsheets.
For statistics on HIV/AIDS disparities among different populations, see the Office of Minority Health & Health Disparities webpage, Eliminate Disparities in HIV and AIDS.
For collections of resources on 22 different populations, many with statistical information, see HIV Insite’s Population Links.
For a collection of reports on youth, see the CDC’s webpage on Healthy Youth: Sexual Risk Behaviors.
For populations worldwide, see the Joint United Nations Programme on HIV/AIDS’s webpage on Key Populations.
For definitions of HIV/AIDS terms and abbreviations, see the U.S. Department of Health and Human Services AIDSinfo Glossary.
For assistance reading and getting the most out of HIV/AIDS statistics, the U.S. Center for Disease Control and Prevention (CDC) has webpages on:
The Kaiser Family Foundation has some resources for better understanding HIV/AIDS statistics:
People sometimes have statistical questions about how likely it is to become infected with HIV from a certain behavior. Columbia University’s Go Ask Alice! Service has a webpage, Confused About HIV Transmission Statistics that helps explain why these statistics can’t be precisely calculated.