Green’s Dictionary of Slang

1. (orig. US, also ten per cent, ten per cent charlie, ten per cent man) an agent who takes ‘ten per cent’ of one’s earnings.

1889		Music Hall & Theatre Rev. 6 July 6/1: Durandeau [...] might fix up the first song for the agents piano ‘Good old ten per cent.’ How does the title strike you ?
1926		Variety 29 Dec. xi 5/4: Broadway chatter is full of theatrical cracks such as [...] ‘ten per center’ [OED].
1935		A.J. Pollock Und. Speaks n.p.: Ten per cent man, a spotter or locator for criminals, who makes a preliminary survey for kidnappers, hold-ups or robberies and receives 10% commission of proceeds obtained.
1939		Pittsburgh Courier (PA) 3 June 11/1: Ten per cent Charlies who buy acts cheaper than they sell them.
1945		R.L. Bellem ‘Coffin for a Coward’ in Hollywood Detective Dec. 🌐 Fortunately the ten per center lived just a few blocks away.
1967		H.S. Thompson letter 5 Jan. in Proud Highway (1997) 601: Punks and narcs and other ten-percenters [...] who managed to get their names on the record jacket.
1985		N. Pileggi Wiseguy (2001) 54: We had to hire ten-percenters just to go and cash our winning tickets.
1999		J. Ridley Everybody Smokes in Hell 33: The big boys at ICM, WMA, CAA — all the power 10-percenters dominoed on Wilshire.
2000		T. Blacker Kill Your Darlings 221: What good would it do me to have some ambitious ten-per-center [...] ?

2. an inadequate, a failure [their success rate/popularity].

1976		Pittsburgh Press (PA) 15 Apr. 29/2: Fast Eddie was a ten-per-center. A ten-per-center is a desperate soul, a busted gambler usually, who will cash in high-dollar payoffs for a price.
1979		(con. c.1970) G. Hasford Short Timers (1985) 31: The recruits [...] will testify that private Pratt, while highly motivated, was a ten percenter who did not pack the gear to be a Marine in our beloved Corps.