Avg Monthly searches & Competition (indexed value)

Hi Guys,

I have updated the tags for my products on Redbubble by the following criteria:

High (Avg. monthly searches) and Low (Competition (indexed value)) by using Google keyword planner. By dividing the Avg. monthly searches by Competition (indexed value), and doing this with all the keywords and adding them up I came up with the exact number of monthly searches in my market share.

I wanted to know does this make sense? Is this the right approach? Please provide suggestions.

Thanks