As PR professionals, we're constantly looking for data and industry statistics to help us round out a story. Market numbers can help substantiate a client pitch and can also be a great way to build relationships with journalists – even if the numbers you provide don't directly correlate to a client story. Imagine stories about the Stimulus plan, the current state of the economy or even the recent "25 Things About Me" craze on Facebook without having numbers to put things in context. How has the unemployment rate changed since December? How many more people logged into Facebook as a result of those notes?

Where can you go to find interesting numbers? Here are a few free Web sites:

Where do you look for good data?

– Contributed by Sue Ferranti.  Follow her @sueferranti.