hard to tell without having proof for this
You can find a lot of posts, and many people saying about 120 blocks in the past. See:
https://www.metzdowd.com/pipermail/cryptography/2009-January/014994.htmlAlso, if you need a source for those "20 hours", you can check this post:
Right, the difficulty adjustment is trying to keep it so the network as a whole generates an average of 6 blocks per hour. The time for your block to mature will always be around 20 hours.
The recent adjustment put us back to close to 6 blocks per hour again.
There's a site where you can see the time between blocks, and since block 68545, it's been more like 10 minutes per block:
http://nullvoid.org/bitcoin/statistix.php