Finding statistics on the web can be a daunting task if you don't know where to look, what organizations or government agencies gather the statistics. For general population or demographic data the first place to go for information about the United States is the Statistical Abstracts of the U.S. or Census.gov website. The US Census gathers the population data then disseminates it into various formats and reports. You can search the Stat Abstracts or use the Index to find particular tables. The Index refers to the "table number" and the online PDF version is the same as the printed version available in the library. The Index has entries that range from the number of automobiles imported to the foreign trading and mining of Zinc.
Although the Census website covers almost any topic overall, there are other government agencies that specialize in gathering statistical information and it is often best to go directly to the source. For instance, for health statistics, if you want to know the number of STDs (sexually transmitted diseases) reported by location you should go to the Centers for Disease Control Data Sets. Most Federal websites allow you to browse by state. For worldwide health data, see the (WHO) World Health Organization.
If you are looking for education statistics you would want to go to the National Center for Education Statistics (NCES) website. Although, the Stat Abstracts above will also offer education related statistics, the NCES is more focused. You can find data on Early Childhood through Post Secondary.
If you are looking for weather data, such as historical rainfall totals or major storms, you would want to go to the National Oceanic and Atmospheric Administration (NOAA) website or the National Climatic Data Center.
There are many more places to search for statistical data and using a trusted source is the first step in getting accurate data. Typically you want to look for government websites. Sites that use .gov or .org rather than .com are the safer bet. If you are still unsure what agency or website has the data you need, when using Google or other search engine, add "statistics" or "data" to your search, in addition to ".gov" or "org".
As always, if you need additional help finding information, please use the Ask a Librarian service!!