The speed at which the list moves depends on all sorts of factors, but it helps if someone is moving it along. Last June I inherited a waiting list of 12 (with several empty plots!). Some dropped out, but most were given plots; meanwhile others added themselves, so I worked through the next lot; finally I allocated a plot to the last applicant (who had phoned me that morning) and I had no waiting list! Since then, I've had at least one inquiry a week. I've just opened up four new plots and currently have a waiting list just into double figures!
Keep plugging away. (And what use is a lawn anyway? Dig it up!)