1000k= 1MB. That's pretty reasonable for a bunch of voice searches, and other voice activity.
I've worked on voice implementations, the data that goes "off-board" is significant, depending on the complexity. Very few things are done on the device itself, in terms of parsing and such, unless it's very simple (like "call home"). Searches would be pretty much 100% done off-board, and the voice data really adds up.