Not much compared with some of you hardcore crunchers, but the first 160 units took me 4 years on a slow old P75:

Results Received                 5890
Total CPU Time                   4.119 years
Average CPU Time per work unit   6 hr 07 min 36.1 sec
Average results received per day 2.74
Last result returned:            Wed Apr 6 07:41:06 2005 UTC
Registered on:                   Tue May 18 06:55:42 1999 UTC
SETI@home user for:              5.891 years

Your rank out of 5392953 total users is:  53293rd place.
The number of users who have this rank:   12
You have completed more work units than   99.012% of our users.