Process:
- Connect Input tool to zip files
- Group by Year and Session, Count SessionIDs
- Split by Session then repeat following process for each thread
- Generate rows from 1999 to 2018
- Union generated rows with data (manual configuration)
- Add session name (e.g. Summer1) if field is null
- Grab unique records (based on Year and Session Name)
- If Count field is null, then calculate as average of Count for two surrounding years
- Union Summer1 and Summer2 threads
- Sum count of attendees at each session (group by year)
- Run through ETS model with target of Count (left all default settings)
Result: Predict 703.1 for 2019