Horwath
Legend
The figure that I've heard is up to 70%.
The plan is to have that happen over a long enough period to keep the death rate down.
That was Merkel's statement for German population.
But, you are right. Plan is to slow the rate of infection so health system is not overwhelmed with critical patients.
And if there is no vaccine in sight, only way to battle it, would be to gain herd immunity and hope that virus does not mutate too much for built up immunity.