Here’s the CDC’s current best estimate of the infection fatality rate (deaths/total infections):
COVID-19 Pandemic Planning Scenarios | CDC (see Table 1 about halfway down the page, “Scenario 5” column)
0-19 years: 0.0003%
20-49 years: 0.02%
50-69 years: 0.5%
70+ years: 5.4%
Here is a Swiss study with similar numbers:
https://osf.io/wdbpe/
5-9 years: 0.0016%
10-19 years: 0.00032%
20-49 years: 0.0092%
50-64 years: 0.14%
65+ years: 5.6%
All: 0.64%
A meta-analysis of IFR studies from around the world:
Under 55 years: “Close to zero”
55-64 years: 0.4%
65-74 years: 1.3%
75-84 years: 4.5%
85+ years: 25%
It’s pretty clear that a single fatality rate across all age groups isn’t very informative. The risk of death rises exponentially with age. In countries like Italy, with one of the oldest populations in the world, the IFR will be higher.