When was the last time that a transaction code executed?

Hi guys!

Could some one tell me please, how could I know (report, table or transaction..) the last time that a transaction was executed? We need to block some transactions that could be obsolate, but before we need to know if there are any user still using them.

I tried with STAT, STAD, but is not exactly what I need... and I don't know how to get the file that it is suppost to get by report RSSTAT20...

Thank you in advance for your help!!

Kind regards,

Carolina