Around 150 or so. I'll go a few months or even a year or 2, without buying, because I get side tracked with other intrests. But I always come back to knives. My current interest is in sharpening, now I need to buy more knives just to sharpen.
Been buying and collecting knives since I was a boy, now 53. If I could make one suggestion to new knife enthusiasts, do not sell any knives. Just keep them, even if you don't really need or use them. And one day you will have a nice and valuable collection, with memories attached. I sold a few when I was younger... the money is long gone, but I wish had the knives now.