How to calculate average chalk layed in NHL

[Waterstpub87]

Tinkering around with making an NHL model. Which is the best way to figure out average chalk in excel.

I tried just to average all of them, but that gave me a number which is too low.
Then made it into a number (-110 to -1.10) but that number seems alitte too high.
Is there a better way that I am not thinking of?

[FourLengthsClear]

Convert each one to the implied win percentage and take the mean average of those.

Implied win percentage of -110 is 110/210 = 52.38%
There is a calculator here, if it helps. http://www.sbrforum.com/betting-tools/odds-converter/

[Flight]

US odds are non linear. Convert to decimal or percent.