Hi,

I'm trying to perform an ABC Analysis (e. g. "'A' customers are those that generate 50 % of revenue, 'B' customers the next 25 %, and 'C' customers the remaining 25 %).

In order to do so, I'm calculating the sales per customer, and sort the list descending by sales, that's simple. But how can I calculate the Running Sum on the sales values?

**Example** **Customer** | **Sales** | ** Running Sum** |

Cust1 | 1000 | ** 1000** |

Cust2 | 700 | ** 1700** |

Cust3 | 300 | ** 2000** |

Cust4 | 250 | ** 2250** |

Thanks a lot for any advice!