75k living Tech alumni?

I heard an interesting stat today at a meeting here at Georgia Tech (where I now work): there are about 75,000 living alumni of Georgia Tech. That's fewer than I thought there would be. There were 15,576 students at Tech in 2001, so 75k is only about five times more than the number of folks currently enrolled.

A few relevant stats from the Tech 2001 "mini fact book:"

• Number of graduates in 2001: 3,370 (2,035 Bachelor's, 1,080 Master's, 255 Ph.D.'s
• Number of students in 2001: 15,576 (11,043 undergrad, 2,359 master's, 2,204 Ph.D.)

So in 2001, about 20% of the students enrolled graduated that year.

Now that I think about it, 75k alumni is about 22 years worth of graduates at the current rate. Perhaps that 75k number is the number of alumni on Tech's mailing list of alumni. That would make more sense.

I wonder which school has the most living alumni?