That would need to be created - see
this guide for the basics on custom statistics creation and
this guide for a deeper walkthrough. While the latter was written for PokerTracker 3 and the user interface is different the techniques still apply to PokerTracker 4. Bear in mind that the statistic will need to be built for the type of report it will be used in - there are existing statistics for daily and monthly hours and you can divide the number of tourneys (
cnt_tourneys) by the number of hours to give you tournament per hour statistics.