Staffa - 10:49 am on Apr 12, 2012 (gmt 0)
Before 2010 the GeoIP database used to be 1.5 MB in size and most IP ranges would be like nnn.0.0.0 - nnn.255.255.255 with a few broken up ones in between. Then at the start of 2010 it all got broken up into splinter ranges like you describe and the same file is now 10.8 MB with 173,415 individual ranges.
One range (184. or 194.b.c.d if I remember correctly) was split into 9,4nn little groups.
If you download the csv file from maxmind dot com you'll have all the ranges and see what I mean.