As reported on GamesIndustry.biz, the number of Early Access/Greenlight games that have actually seen finished releases is around the 25% mark.
This means 75% of the games are either still being made, or have been abandoned entirely. It's not unexpected - it's certainly not an inherently bad thing - it's just interesting to see the figures laid out so starkly.
There's a lot more data and graphs over on GI beyond the headline statistic, so I'd recommend going over there and taking a look.
What do you think of Early Access games? Have you picked any up? Are they not for you? There's a comments section below, let's chat.