Calculate average of only unique records

Hello,

I'm working off an Excel spreadsheet linked to Power BI and I'm trying to find the average income of just unique Families.  

For example, in the sample below, using the Average option in any PowerBI value field results in the average of all rows, in this case, 50,631.25 since a single family is listed multiple times (depending on their household size).  I'm trying to get the value listed under the 'UniqueAVG' column, 52,060 - the true average income for families in the sample.

Is there a way to accomplish this either within PowerBI or from Excel?

Thanks!