If you’d like to figure out how much each customer has spent in the past year, or just identify your top spending customers, you now have access to a new report that generates a total spend based on customers. 

To access this feature, first navigate to Sitemap -> Payment Report. 
Then, click on the “Calculate Customer Total Spend” link. 

You can optionally enter a Tag value to filter results. The report will find all customers with that tag and generate a total spend report, which will then be sent to you via email.