As RingCT approaches I think volume has the potential to go much higher. I have looked at ZCash very closely and still find Monero much more attractive. If a reasonable percentage of the people hearing about ZCash this summer prior to its release perform due diligence, I think a lot of new interest in Monero will result.
So we won't count on any new interest from that quarter.
Volume throughout cryptoland has been through the roof this year. Monero awoke from its slumber with the Hydrogen Helix release, but didn't launch until early February when everything started to explode. Awesome timing, devs. 0.9 has made it so much easier to get involved. So many things coming together in 2016.