The increase over the last few years is total b.s. if you ask me.
After 1995, many JW's saw that the end wasn't so imminent and many had children. Those kids are the majority of the ones getting baptized over the years. I know they only count "active" ones, so many are still active, but I think they really peaked at 6.9 to 7.0 million. They switched to allowing "15-minutes-a-month" elderly ones and a few others. I can imagine the hounders begging every senior citizen to consider whether they "preached" at all in the last month. Add that to the number of faders that don't actually put their time in recruiting, but report at least one hour to keep hounders away. There's also parents that count time with their children but don't actually do the time at all, or go door-to-door.
I think you will find that they peaked about two years ago or so and are actually on the way down. They had a boost from Sept. 11th, 2001 but that was so long ago now that many of those faded again or walked away again.
If they are actually going up, it's hardly from door-to-door work, but from family witnessing and the likes.