[Koha] Looking for a bit of report help

[Nicole Engard]

I'm looking for some help with reports that require more math than my brain
can handle.

#1: circulation by % coll code within a date range [50% of DVDs circulated]

I have this one:
http://wiki.koha-community.org/wiki/SQL_Reports_Library#Percentage_of_circs_by_collection_codebut
I'm not sure how to alter it to show the percentage of the DVDs in the
collection instead of the percentage of all check outs.

#2: DVDs circulating 50% of total DVDs where DVD is a collection code

This might be the same as the above ... unless you all read it differently
than me.

Thanks in advance,
Nicole