on average 平均で

on average (on the average, on an average)大体、概して、平均で、などの意味がある。1:30 on average, earthquakes kill about 10,000 people each year.

Earthquakes 101
https://www.youtube.com/watch?v=ySG2AwpSZmw  1:50 on average, such patients survive less than a year.皮膚がんが臓器に転移した患者の余命は概して一年未満だ。
James Allison's Cancer Research Breakthrough
https://www.youtube.com/watch?v=Hhw9B7T71ok  2:18 on average, young people don't leave home until they are 24. 　
Children should have longer to adjust from being in care (11Jun13)

0:39 on average, people in the middle will get an $840 break in 2019.

Tax cuts: Broken promises