And, since everyone was just dying to know, I ran it with Increment=100 over lunch. All things considered, it seems like 10000 is a happy medium although with truly large files (100+ million), perhaps 100000 is a better choice.

Jim

100
NOTE: DATA statement used (Total process time):
real time 31:55.86
cpu time 4:24.38

1000
NOTE: DATA statement used (Total process time):
real time 4:09.70
cpu time 41.51 seconds

10000
NOTE: DATA statement used (Total process time):
real time 1:50.68
cpu time 18.03 seconds

100000
NOTE: DATA statement used (Total process time):
real time 1:40.14
cpu time 15.56 seconds

1000000
NOTE: DATA statement used (Total process time):
real time 1:37.27
cpu time 15.42 seconds