How to increase the % of indexed-queries?

Dear Sirs,

We got low 0% of indexed Queries.
I’m very worry about that. If there is anything that I need to config? Or if it’s normal to get 0% of index Queries ?

PS: I got 0% of index queries from “Database -> Monitor-> DatabaseMonitor”.

My Oracle is v9.2.0.4, TOAD is 9.0.1

Thanks a lot !!