I must admit I haven't ever thought about these numbers but it strikes me as insanely high. How can this be explained? Is it a feature of just America or is it reproducible in other countries as well?
"... that almost a third of men [in Britain] have a criminal conviction by the age of 30, according to the Home Office. Research on men born in 1953 showed that about 30 per cent had clocked up a standard list offence - one that is dealt with by the courts but excludes minor motoring offences - by their thirtieth birthday. Research in Scotland points in the same direction, suggesting that about 25 per cent of men have a record by age 24."
https://www.theguardian.com/money/2002/apr/14/workandcareers...
The net cast by law enforcement has not gotten smaller since then.