have you tried with
Server jobActivity "start date" "end date" Server_Name
date format: 2008-01-29 01:02:03
it would make more sense to do this in bdssa.
From query studio
--> Job Activity domain,
Job name -->right click to get the count of jobs
Job run time-->Filter on this filed to specify the date period.
Create a simple report with these 2 fileds to shows #jobs for specific time period.
As suggested by Bill before, we can do the same from the BDSSA reporting..