I think it has been about 5 years, but the years are going by much differently now than they did 20 years ago hard to say for sure-and I don't have my list where I can find it.
It was an ok size about 3 years ago in a fair amount of shade. We had the mother of all ice storms in Dec '08 and I lost all the shade at that end of the yard so WP was in full sun last summer and it grew much larger. It did look kinda tired by August (remember we have 100+ degree heat here in summer), but it seems to like the sun! It has keep that great coloring for over a couple of months now!
Mine has been a pretty fast grower, and I attribute that to giving it a lot of light.
I believe a perfect War Paint leaf in the spring is perhaps the most attractive hosta leaf in the world. When the centers are still lighter than the photo here, you can find every color of the hosta rainbow, from blue through greyish and greens to chartreuse, yellow, and cream, with good mixing and streaking of all the colors.
some folks bad mouth War Paint because the striking color combination doesn't last very long. I always point out that after the leaves turn all green, one really sees the neat rippled edges - I think, in fact, that War Paint may be the most attractive large green hosta in the world. Like Queen of the Seas for the blues, and Dancing Queen for the yellows, I think WP sets the standard for large green rippled leaf hostas.
No pics from me this year... WP is in a north area of my garden and was one of those particularly affected by our cold snap... some damage showing on close to half the leaves. Still, I show off the undamaged leaves to every garden visitor... what a beautiful plant!
War Paint gets a lot of comments now when the centers are light colored, and next month when it is solid green the tags will be changed to Niagara Falls and it will still get a lot of attention.