What I learned publishing 80 sourced statistics before launching

Before launching our app I spent a day building a page of 80 statistics about drop-in fitness in the US, each with a primary source, a data year and a permanent anchor link. Three things I did not expect: 1. Most "industry statistics" you find are blogs citing blogs. I dropped about a third of what I collected because I could not reach a primary source. Gym churn numbers are the worst offenders. 2. Writing a script that re-fetches every source and checks the figure still appears in the document caught a real mistake: I had written that 67% of members pay under $100 a month, when the source says under $50. That would have been quoted back at me. 3. The page is now the thing I send to journalists instead of a pitch. It works better than describing the product, because it gives them something to use. The boring part is the verification, and it is the part you cannot skip: one wrong number quoted in an article is permanent. For anyone who has done this: do you keep the sources in the page itself or in a separate document, and how do you handle a source that goes offline a year later?