“I think you are missing the point...”
I hope I’m missing your point because it going nowhere.
And as to your assertion that schools like MIT never took the top 1%, duh. If only 5% were going to college, and MIT only took those in the upper 20% of college students, that would be 1%. During the war, I am sure that MIT got somewhere above the first percentile — you know, developing radar and all.
Correct me if I am wrong, but I’m beginning to think you are not 1%er, or 5%er, but perhaps 35%er?
However, if you want some facts, take a look at Table 24 of this reference. I'll summarize the key numbers for you:
Year | College enrollment as % of 18 to 24 year olds |
1939-1940 | 9.1 |
1941-1942 | 8.4 |
1943-1944 | 6.8 |
1945-1946 | 10.0 |
Fall 1946 | 12.5 |
Fall 1947 | 14.2 |
Fall 1948 | 14.7 |
Fall 1949 | 15.2 |
... | ... |
Fall 1991 | 53.7 |
So the average for the '40s is roughly 10% of the college-age population (about double your 5% number). However, this is not the top 10% of the all of the students, as "College education was reserved for an elite, socially homogeneous group of students (Bloomgarden, 1961). The students in college in the early 1940s were predominantly male, overwhelmingly white, and from middle- and upper-class families (Rudolph, 1990). Because higher education was primarily funded through student tuition and with only minimal aid available to students in the form of scholarships, fellowships and state government funds, college was primarily affordable only to the middle and upper class".
While I would surmise that most of the middle-class students would be in the top 10%, my guess is that there were a fair number of upper-class students who were not in the top 10%, even at the most prestigious universities.
As for the current state of affairs, I cannot say how many students at MIT or Caltech are in the top 1%, but test scores of the current MIT class can be found here, and 94% of Caltech's students were in the top 10% of their classes. Also, from personal experience, the students I know from these institutions for the most part were in the top 1 or 2% of their classes, at least that was the case 30 years ago.
As for Caltech, in 1945 there were approximately 700 undergraduates. In the mid-80's, it had roughly 880. Today, it has roughly 980. Not a big increase in enrollment compared to the number of students of college age at those times.
I could assert, but not prove, that these schools are actually more selective, since the number of student in college has dramatically increased, but not the number of students at these schools.