VER ACTIVIDAD DML

SELECT TABLE_NAME,INSERTS,UPDATES,DELETES
FROM USER_TAB_MODIFICATIONS
WHERE TABLE_NAME='TABLA'

It is possible to manually flush this data by calling the procedure DBMS_STATS.FLUSH_DATABASE_MONITORING_INFO if you want to get up-to-date information at query time (internally the monitoring data is flushed before all statistics collection operations). You can then see which tables have stale statistics by querying the STALE_STATS column in the USER_TAB_STATISTICS view