Solr Dismax using % in mm parameter give error

Question

I am trying to use the mm (Minimum Should Match) parameter with the dismax parser. If I do just mm=2 or any other int value it seems to work fine. But if I try and add a percent as shown in the able, say mm=60%, then I get an "invalid digit" error for the query. How do I actually use the percentage for mm?

Solr ref guide mm table

(running solr 7.6 btw)