This is the full-history chart for one advertising account. It stays close to flat until 2019, climbs through 2020 and peaks in early 2021.
Across the whole period, $360,376.26 of spend produced $1,715,559.68 in attributed sales from 10,156 orders. That is an ACoS of 21.01% held over years, through the scale-up as well as the quieter months.
