The first column is the interest id – presumably reflecting the order in which interests were added to LiveJournal. The second column is how many people have that interest.
What is your lowest-numbered interest? What is your highest?
What is your most popular interest? Least popular?
My lowest is interest #1, Linux. I also have #2, programming. Sex didn't make it in until #33. How obvious is it that the first users were nerds? :o)
My highest number is one that I added myself: #6,176,256, non-wiccan paganism. It's also my least popular, being unique to me (for now...)
My most popular interest is #22, music, which I share with 1,376,499 other users.