Big Data analysis can involve massive amounts of data and complex analysis. However, you know that some of the simpler customer relationship management $($CRM$)$ metrics are often a good starting point for firms seeking to increase their profitability.

It is well$-$known that retaining an existing customer is far less expensive than acquiring a new one, so you suggest that the owners begin by calculating share of customer to identify opportunities to sell more products to existing customers. Before you can calculate Camp Plus's share of customer, you need to determine what type of data you need to gather. What data sources will you need to utilize to calculate share of customer?