Assuming you have a bunch of tab delimited files w/out headers and the second column as a number, you could use the following powershell command to sum the values and output the result.

PS > $sum=0; ls | cat | %{ $_.split("`t")[1] } | %{ $sum+=[int]$_ }; $sum

Sample File:

a-count    7
b-count    233
c-count    32