The Fifty Stop file or table in the results set contains the following columns:

sStateProv	The two digit FIPS code that identifies the state or province the route was run in.
sRoute	The three digit code that identifies the route.
iYear	The year. The sStateProv, sRoute, and iYear columns uniquely identify a run of a route.
sAou	The five digit AOU code identifies the species.
iStop1..iStop50	The number of the species recorded on each stop on that run of the route.

Fifty Stop data is currently only available for 1997 and later, and a few earlier routes.

There is one row in the Fifty Stop file for every species on every run of a route that matches the query.