I tested your code with a different csv file where all the columns had the same length and it plotted the correct number of bars. I suspect that's the source of the problem since you only have 3 complete columns in your data. Also, lines 15 through 43 of your code (all the for loops and append statements) can be replaced with a single line:
tc = [sum(rgn1), sum(rgn2), sum(rgn3), sum(rgn4), sum(rgn5), sum(rgn6), sum(rgn7)]
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