I have a table of data as below. There are more Customers, and more dates'
worth of data, but they won't fit in this window. For a number of our
customers, we change delivery routes during the week in order to optimize our
shipping capacity. Basically, I am trying to see for each delivery route, on
a given day, how many of the same customers are on the same route. In other
words, when one customer changes from one route to another over a date range,
do other customers switch to the same routes on the same days?

Cust # Rt# 8/27/2005 8/29/2005 8/30/2005 8/31/2005
a 1069
a 1081 1
a 1088
a 1090 1 1
a 3271
b 1003 1
b 1076 1
b 1089 1
b 1101
c 1069
c 1071
c 1081 1
c 1082
c 1090 1
d 958
d 1069
d 1070
d 1072
d 1080 1
d 1082
e 1069