Weighted Mean - Panel Data

[jhh]

I'm using EViews 8 and I have a panel workfile. I have data for 900 districts from 1966 to 2011. The districts are my panel variable. Amongst my variables I have TFP and AREA FOR ALL DISTRICTS FOR ALL YEARS.
I need to check the TFP on the country level yearwise. So I need to compute calculate the weighted mean of a variable (TFP) using AREA variable as weights.
I can’t find the way to use area variable as weights. Kindly let me know how I can do this.
I went through an earlier query which seemed similar and followed the code but it did not help to generate year wise TFP figures.

Thanks a lot