How to calculate the ratio insert/select against a table?

To create/manage indexes of a table, it is important to know the ratio INSERT/SELECT aka MODIFICATION/REPORT.

For instance, if there are more INSERT than SELECT queries against a table, we should try to create only a few small indexes not to impact the  performance of the SELECT queries.

How to calculate this ratio in Sybase ASE 15.5 and later?

I propose the following MDA query. Is that correct?

select "Table"=object_name(ObjectID), IndexID, PagesRead, PagesWritten, Operations

from master..monOpenObjectActivity where DBID=db_id("DBNAME") and ObjectID=object_id('TableNAME')

order by IndexID

Thanks,

Vincent