Does Catalog contain the information of index insert/update/delete tuples number ??

hi :
pg_stat_user_tables store the n_tup_ins,n_tup_upd,n_tup_del information, and those information is very useful.
I check the pg_stat_user_indexes table, but there are no such information.

can i get such information in other way ?
or system catalog does not store such information !
or those information can be derived from other statistic ?

i want use these information to tuning the index
please give me some suggestion!
thank you very much!

Kao , Nchu Taiwan