Twelve years later and I've done 175 of them.
I've made it hard for myself up to now by tackling the problems in numeric order - not skipping a problem even if it's boring or hard - so the highest number problem I've solved right now is 175. Also, I've been taking regular several-year breaks.
They're adding new problems much faster than I'm solving them (the latest one is number 650), so now I'm thinking of skipping to the latest problems and having a go at a few of those - the discussion on those is bound to be more lively than the ones that were added a decade or more ago.