I'm continually asked to provide a statistics on how many parents read the reports generated through the Portal Publishing section of the Report Printing module, honestly it would even be useful to tell which parents have download reports but we can't even do that - I know we can see when they have most recently logged in but we can't tell what they are doing so can't guarantee that they have read reports.
There is a 'Legacy Portal Statistics' part of the portal but that only tells us about bandwidth or type of files downloaded, and pdf isn't even included in the list of file types so must come under 'N/A'.
The best workaround I've found is to copy/paste the history from Document Options, run the Portal Users Last Login with Pupil ID separately and export pupil records from Pupil Manager. Then put it all into Google Spreadsheet and run a lot of XLOOKUPs to get a basic overview.
However the history from Document Options doesn't seem to capture everything (?) and the Portal Users Last Login with Pupil ID report has issues when a parent has multiple accounts. So this workaround is far from accurate.