Scouting Reports

Is there any trick involved that gives more scouting reports?
Currently i am running T16 maps with at least 70% item Quantity.
Using scarabs and sextants. Also using delerium as much as possible.
Any other ideas cause they are simply just not dropping for me.
Earlier in league they were dropping ok but a very rare for me now.
Thanks.

There are nodes on the atlas passive tree. I haven't taken them and they still drop frequently in low-investment maps. I tried burning through a ton to farm harvest and still have about 350 in my stash.

Forgot to mention i adjusted my atlas to include the 3 Kirac nodes.