Oh, come now Roussette. Yes, you are quite right, your post did not mention Kate. You said:
”Read this link. 74% royal patronage charities did not get any visits in one given year. For others, it has been far longer than a year. Even 8 years for one charity”
If you read your link, as you extort us to do, you can see that the sixth paragraph states: In fact, most UK charities with Royal patrons did not get a single public engagement with their Royal patron last year: 74% of them got none. Only 1% of charities with Royal patrons got more than one public engagement with them last year. {In this video, it transpires that Kate hasn’t visited one of her patronee charities for eight years.}.
So, given that paragraph that matches the statistics you gave us, it seems fairly clear that you intended to refer to Kate as the Royal who hadn’t visited a charity for eight years.
Of course if that’s not the case, please do know let us know which specific Royal it was you were referring to there, and we will stand corrected.
The report may be very detailed. If they choose to make such sloppy errors, and refer to such dubious sources in their introduction however, readers are free to make up their own mind about their value.
(Also, it is utter common sense that the charities that have a Royal Patron don’t get a visit a year. The Queen and the Duke of Edinburgh held over a thousand between them - see www.royal.uk/charities-and-patronages-1. Mathematically speaking each of would have needed to visit 1 or 2 most days to achieve that. 
It’s one of the reasons why the younger generation of Royals have talked about taking on fewer patronages in order to be more visible in their roles).