Here is a summary of my analysis for the UK. I believe that the US will not be very different.
The true unemployment rate (including the excess of normal levels of youngsters economically inactive) is 9.3% and this is heading up step by step towards 43% in 23 years' time.

UK 2013 2019 2025 2031 2037
Unemployment rate Inactive Unemployment rate Inactive Unemployment rate Inactive Unemployment rate Inactive Unemployment rate Inactive
18-24 18% 29% 25% 38% 35% 50% 45% 54% 45% 54%
25-31 7% 16% 10% 25% 25% 38% 35% 50% 45% 54%
32-38 5% 15% 7% 16% 10% 25% 25% 38% 35% 50%
39-45 5% 15% 5% 15% 7% 16% 10% 25% 25% 38%
46-52 5% 15% 5% 15% 5% 15% 7% 16% 10% 25%
53-59 5% 30% 5% 30% 5% 30% 5% 30% 7% 31%
60-66 5% 40% 5% 40% 5% 40% 5% 40% 5% 40%
Total 7% 23% 9% 26% 13% 31% 19% 36% 25% 42%
Total true unemployed 9.3% 13.4% 22.0% 32.6% 43.2%