From the table, it's difficult to tell which service is most profitable. On average, customers spend the most on equipment rental, but there is a lot of variation in the amount spent.

Customers with calling card service spend only slightly less, on average, than equipment rental customers, and there is much less variation in the values.

The real problem here is that most customers don't have every service, so a lot of 0's are being counted. One solution to this problem is to treat 0's as missing values so that the analysis for each service becomes conditional on having that service.