Hello Carol, is this a query regarding Solutions for Db2? I will move this to the right product community accordingly.
The WKLD_ STATISTICS tables are aggregated by non-statement collection key (plan, program, user, and so on)
per defined collection interval. But they are still within an interval. The BASELINE version of all the tables represent acceptable performance, for example after you have tuned an application, or reorganised all the tables.
If you want to aggregate at a longer period there are DAILY_WKLD_STATISTICS, WEEKLY_WKLD_STATISTICS, MONTHLY_WKLD_STATISTICS which should do what you want.