But anyways, how many people died from the wildfires started by power lines?

Certainly fewer than succumb to natural gas related causes. Nationwide somewhere around 15 people die annually from pipeline related incidents, over 400 from carbon monoxide poisoning.

California's got a long history of safety problems with natural gas:

https://la.curbed.com/2016/3/8/11181374/gas-leaks-los-angele...