Crashyltics CFR for a time range is lower than the lowest dip in that range

Whenever the CFR goes down 98% we need to make a 30 days rep开发者_运维问答ort and show it to elders at work. This is the first time I am doing this report.

I noticed the lowest dip was 97.93 and yet the CFR for last 30 days is 96.35. Please see the image.

I read that this (here) figure is aggregation over time and the formula used is

CRASH_FREE_USERS_PERCENTAGE = 1 - (CRASHED_USERS / ALL_USERS) x 100

Question in context: For the last 30 days range, If the lowest dip is 97.93%. Then how come CFR is 96.35% for that range.