Relative to other periods it was practically zero, in other words quite neglible.
Between 1930 and 1950, legal immigration never exceeded 250,000 a year, and plunged to 23,000+ in 1933 and 1943.
The worst presidential administration for legal immigration in the post-war is George Herbert Walker Bush's. In fiscal 1991 he let in over 1.8 million
You can examine the interactive chart, here.