Report on rules with zero hits

[StevePearson]

I'm working on R81.20 with the latest jumbo, and need to get a report of rules with zero hits.

Ideally I'd like to be able to run this on a schedule, for example every week, to show rules with zero hits in the last 90 days.

I've seen several things about this, some suggest using a mgmt_cli command, some suggest API, but nothing definitive.

As a temporary workaround I've exported the policy to CSV but the hits column is not populated despite the hits showing correctly in SmartConsole!