I can't give you an exact percentage. I know I had around 10 or so, could be +/- 2. I was happy to get that many, calculations are much easier than the scenario based stuff...you either know the answer or you don't.
EDIT TO ADD: I purchased the Formula Study Guide from Cornelius and crew and found it to be invaluable.
Moderators: Yolanda Mabutas, Ahmed Amin, Scott Gillard, Mary Kathrine Padua, ERIC BARTLETT, Gail Freedman, Kevin Nason, Steven Mudrinich, PMP, Mark Wuenscher, PMP, John Wolverton, Tracy Shagnea, PMP, Jada Garrett
This interview with Simona Fallavollita (LinkedIn Profile) was recorded at the magnificient Project Management Institute (PMI)® Global Conference 2017 in Chicago, Illinois. We discuss the how, what, why and when of the changes that are coming to the PMP exam.