I've provided some hints in the similar topic: How to Access Number of Views for Pages on Data Center (On-prem) Confluence?

The question there was explicitly restricted to Confluence Data Center (i.e. not cloud version of Confluence). The short summary of my reply by named topic is: there is no suitable official REST API for Data Center version available, but there are some tricks, which could be useful (however the interface might be restricted for usual users).

Current topic is not limited by Data Center version and in the Cloud version of Confluence - the REST API interface was extended, so now it could provide the statistical information. Please see the details here: https://developer.atlassian.com/cloud/confluence/rest/v1/api-group-analytics/#api-group-analytics