Here’s my totals on Time Presidential cover apearances.
Hoover 2
FDR 8
Truman 7
Ike 7
JFK 9
LBJ 11
Nixon 37
Ford 15
Carter 17
Ronald Reagan 28
GHW Bush 11
Clinton 26
W 19
0 8
I forgot to add that these are grand totals, especially for Obama since Time Ragazine started. That number also includes before the last election.