In addition to substr being faster than a regex, your code is computing: 
1/@data

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200,000 times. Computing this value only once before looping over the data and storing the result into a variable is very likely to save you some significant time (but benchmarking and/or profiling would be needed to say how much time). Storing the result of a computation to avoid re-computing it many times is called caching or memoizing (see for example https://en.wikipedia.org/wiki/Memoization) and is a very common optimization technique.

In reply to Re^3: Weighted frequency of characters in an array of strings by Laurent_R
in thread Weighted frequency of characters in an array of strings by K_Edw

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