temper command

Dear all,

  When I use the temper command,which command can I get the acceptance ratio?
The temper command create some replica,so I don't know physical quantity 
Follow is my form of the command,
 variable t world 650.0 700.0 750.0 810.0 880.0 970.0 1080.0 1210.0
 fix     a1 all nvt temp $t $t  0.1 
 temper 1000000 5000 $t a1 3847 58382
 unfix           a1

Thank you very much for your time!

With best wishes,