They haven't publicly released sub numbers, nor do I expect that to change anytime soon. But they're for the most part stable, and work their asses off to appeal to the crowd they have, rather than gloat about big numbers as a draw for why others should play it too.
Do you know anyone playing? If yes, great. Don't need to know sub numbers. No? Well you can meet people as that aspect is still very much alive and kicking. And X million or X+2 million players doesn't make or break a game, just look at EVE.