How are you able to sum values cumulatively, so that all previous values are added into the most recent value? For example, I have the following values: Storm     Value XXX        1 AAA        2 CCC        3 BBB         4 However, I want the 'value' section to be added cumulatively to get this instead: Storm     Value XXX        1 AAA        3 CCC        6 BBB        10 ... View more