After reading through the Top 5 by Region thread it dawned on me how many top courses can be found in NJ, NY and PA. I looked at the the different magazine lists and determined that there are a staggering amount of courses by both percentage and volume when you take into account the sample size. Certainly worthy of a BIG 3 designation.
On the Golfweek Classic list there are 6 of the Top 10, 10 of the Top 25, 17 of the Top 50, 23 of the Top 75 and 33 of the Top 100.
On the Golf Digest Top 100 list which makes no distinction between classic and modern there are 22.
On the Golf Magazine World Top 100 there are 15.