Who else tracks their MPG (any format)

[NirvAveo]

I use the app Fuelio, it does a similar job to the app you're using. It has graphs for your usage and patterns of improvement/worsening fuel economy etc. In South Africa we usually use litres/100km though. The quoted average for Aveos (up to 2009) is 7.3l/100km, and I'm getting an average of 7.8 (which is ~30mpg).