Who has sustained creativity over the longest period, as measured by the gap between the earliest and latest appearances on the list?
Not too many prizes for guessing Bob Dylan. "The Freewheelin' Bob Dylan" was released in 1963 and gave us "Blowin' in the Wind", "A Hard Rain's A-Gonna Fall", "I Shall Be Free" et al. His most recent entry is 1998 - a 36 year "career" (ironically a live recording from 1966). "Time Out of Mind" is the most recent new recording - released in 1997. I wouldn't be surprised to see another entry from the old Bob before he shuffles off.
Johnny Cash had a renaissance just before he passed and is just behind the old Bob with 35 years. "Johnny Cash At Folsom Prison" was released in 1968. Who else could sing in a prison concert "Well I laughed in the Sheriff's face and I spat in his eye."? In 2002 he was back with his third entry, "American IV: The Man Comes Around".
The 20 Year Club
Bruce ! (Springsteen) 5 entries over 28 years with the most recent in 2002. Surely he's got a few classics left in him?
Emmylou Harris - two entries over 26 years. Go girl.
Robert Wyatt - two entries over 24 years - one of those artists I've always meant to check out.
Neil Young - of course - seven entries over 22 years with the most recent in 1990. Now he could definitely pop out a classic any time, which would put him into third spot.
Leonard Cohen rounds out the 20 Year Club - four entries over 21 years. His recent concerts in Sydney were very well received - so he must also be still regarded as a threat.
Long Service Leave (over 10 years)
Portishead, Nick Cave, Radiohead, Green Day, Slipknot all made their first appearances in the list 1990s.