Is it safe to assume the vast majority of Russian soldiers are males between 19-30?
If so, based on the population breakdown that I looked up, Russias casualties are just under 10% of their entire population in that demographic in the first year of this conflict.
19 to 30 would describe the age of conscripted personnel, but the conscripted personnel have not be much used in Ukraine. It's against Russian law for them to be used unless Russia declares that this is a war.
In Ukraine they have been using mobilized personnel and they would be more like 35 as an average age. A lot of them will be old men.