Macro to Sum several data sets(variable length) in the same column

Hey Guys,

I need help to create a macro which adds up the data in column I and places it somewhere in column M. The dataset is variable each time and is separated by a blank row. So what I want is I want to add data from column I1 to I11 (in this case) and paste it on M11 and then I want the sum from I 13 to I 19 and Paste it on M19. Like I said, the data is variable so I cant figure out how to add the formula. Can someone please help. Thanks in advance.

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