My Excel 2010 data (simplified) looks like this:

```
Product ID Product Family Safe For Kids Under $10 Free Shipping
---------------------------------------------------------------------------------------
1 Housewares 1 0 1
2 Pots-n-Pans 0 1 0
and so on...
```

I want to end up with a "clustered column" chart which shows, for each product family, the percentage of products in that family which are "Safe for Kids", "Under $10", or have "Free Shipping". Each product family should have three bars each, one for each percentage.

It's easy to do this for absolute values by using a `sum`

in my PivotChart for each column. But I can't figure out how to turn those sums into percentages of the total number of rows in each category.

Any ideas?