15% of Peoples’ Democratic Party (HDP) voters to say ‘yes’
Kurds for Erdogan!
Not an insubstantial demographic - there are quite a lot of conservative Kurds (heck, Turkey's Kurdish population is exploding dramatically, so they really need those votes).
I understand that there is a Kurdish Hezbollah? Most Kurds are rural and generally poorer and less educated than other Turks, so it follows that some of them would be conservative, at least more naturally than them being feminist pro-LGBT left-wingers (which is what most of them
do vote for).