Well, I don’t think that number of translations has much to do with the number of speakers but rather the amount of time the languages have been around: Esperanto for over 100 years and Klingon less than 25 and I suspect that Esperanto’s glory days are behind it.
Nevertheless, after looking into it, I think that you’re right about the relative numbers of speakers. There aren’t really any good surveys but the rough consensus is that there are about 10,000 fluent Esperanto speakers with about 100,000 who can stumble along it rather like people who took French in High School and still have their text books but never really used it. Klingon is an order of magnitude below that: about 1,000 fluent speakers with 10,000 who can stumble along. In comparison, one of the aboriginal languages of Peru has about 4 million fluent speakers. I wonder how Latin compares?
I don’t think Klingon is doing too badly, considering it’s newness, but it has a lot against it. The vocabulary is really small and mostly deals with things from the future that don’t exist yet. It’s also probably copyrighted whereas Zamenhof was a pioneer of open-source with Esperanto as he renounced his copyright from the beginning.
