I've worked the numbers a few times over the years, and it's impossible for the 144,000 figure to be literal. What it means is that there were essentially only 100,000 or so "true" Christians from Pentecost 33 CE until the 20th Century, with the rest of the 144K showing up from 1900 until 1935 or so when the Great crowd began to be gathered. That's the gist of the WTS doctrine on the matter, and it is just completely nonsensical.
First of all, there are historical accounts of tens of thousands and even hundreds of thousands of early Christians being slaughtered during those first centuries. Even allowing for huge exaggerations in the numbers, it would still be far more than 144,000.
The WTS has gotten around this by stating that many of those early Christians weren't really "true" Christians, but were part of the great apostasy and Christendom. One of the ways they show this is by referring to these people being slaughtered and how many of them were claiming supernatural events in their life, such as seeing visions as they were being killed.
So, Stephen can see a vision as he's being stoned, and he's an anointed true believer, but 30 or 50 or 70 years later the same thing proves the person is a part of Christendom??!!
Then the WTS says there were always members of the anointed alive down through the centuries until modern times, which must also run into the tens of thousands, at least.
Their taking the 144,000 figure as literal has long been a joke, and these bouncing number of partakers over the years is a thorn in their flesh. I used to keep a running tally on a card listing the number of partakers each year when I was a JW. This number is of huge importance to active JWs.
What I found was that from the 60s to the 90s, the number of anointed increased 1 out of every 4 years, on average. So, 25% of the time the number of anointed goes up, though there was overall a general decline in the numbers - until it got down to around 8500.
My guess is that that figure might even be higher now if the last few years are included. But this jump of 10% has got to have them crapping their pants. It flies in the face of all the WTS theology.
They will mark it up to weak and mentally ill ones partaking due to the May 2007 WT QFR quoted above, but it's still a serious problem for them. The literal 144,000 has been a huge weak spot in Witness doctrine for a long time, starting with the fact of taking the number literally while explaining everything else around it as symbolic.
This jump in anointed is a serious issue. Watch for a WT article, very likely a study one, about examing your claim if you have started partaking.
S4