What are the Verizon netblocks for mifi connections?

[syuroff]

Hi all,

Our office uses a backup system that will push backups over WAN connections.  I would like to add some firewall rules that would deny backups from devices connected through the Verizon wireless network, so we don't go through the 5 gig cap prematurely.  Is there a resource that would list the specific netblocks that Verizon uses for wireless data- specifically MiFi's, in case they're different than other network devices.

I have previously blocked 75.0.0.0/8 and 72.0.0.0/8, but that's smashing the problem with too big of a hammer- it's also blocking some of my users from non-metered connections.  I need to focus down on the specific networks that are used by verizon wireless devices.

Thanks!