Some of you have seen this before, or an earlier copy of it.

This is my daily commute, over the last 1.5 years. 500+ data points.

125% (above full on the gauge) and 1% (empty / low fuel light) both have 1/3 as many data points as the others.

My car stumbles / sputters a bit when it gets low, but still has fuel. I haven't run it dry yet. I may need to fix something there.

I have an 11 gallon tank.

Q3 is the 75th percentile, or halfway from average to max.

Q1 is the 25th, or halfway from average to min.

The linear portion (25%-125%) of the mean chart calculates out to about 0.5% decrease per gallon added.