See scottmurray.org for the latest, including a new book project. This website is not current and will be retired at some point.
It used to be that once data was published in PDF form — such as on a government website — it was as good as dead. Fortunately, lots of smart people have been developing new tools to help use extract tables of data from PDF and export it in structured, usable formats (like CSV).
Here are the tools I’ve found to be useful. Results may vary as each tool has its own strengths and weaknesses; try them all to see what works best for your document. (If you know of others, please let me know.)
For those curious why it’s so difficult to pull data out of PDFs, you might enjoy this read from ProPublica.