Why do you use visits per year as opposed to keyword volume?

Keyword volume for a single keyword phrase is meant to make decisions on which keyword to go after via Google Ads, not for writing blog posts. As a blogger, you want to be looking at the total Google traffic you will get based on your most likely ranking. This is what RankIQ gives you in the estimated visits per year metric. The visits per year calculates the actual number of visitors driven to the current blog posts ranking on the first page of Google for that keyword phrase. This includes all keyword variations. Keyword volume is just the number of searches on Google that occur each month for that exact keyword phrase.