Daily Ticket Sales Count, rather than Cumulative Count

Hi all,

This is probably fairly straightforward, but I can't quite figure out the filters to get my widget to show ticket sales count by day only. I'm trying to do a line graph that shows the total ticket sales count each day for the last 7 days, but the number appearing is cumulative for the production, rather than what was sold that day only.

Appreciate any assistance.

Many thanks, 
Em