According to Wikipedia there have been 4.3 fatalities for every 100 summits (generally decreasing over time), but that can't really be meaningfully expressed as a mortality rate because the fatalities include people who never reach the summit (and may not even have planned to). What can be said is that of those who successfully reach the summit, 1.1% die during the descent.
My advice, take her on a trip to Paris and Versailles instead... or climb Mount Everest if you're more adventurous. We have great memories.