[bhartzer]

I wouldn't use Keyword Planner for keyword research data. The keywords that appear there are only being actively bid on. So keywords that have more search volume and no ads won't be included.

[amoorthy]

This is a great point. Can you please confirm with a source (or other commenters confirm)? Thank you.

[davidwihl]

You can use the Traffic Estimator Service

https://developers.google.com/adwords/api/docs/guides/traffi...

Disclosure: I work in Google DevRel on this API

[craze3]

What are some good alternatives ?