New to Stackexchange, so I'm not sure how to build a graph. Instead, belowBelow is a picture of how to use excel to calculate the necessary values in order to get the Gini Coeffecient.
Once you get the total value, the Gini Coefficient is calculated as $1-total\ value$$1-\text{total value}$, which in this case is $1-0.733=0.267$ rounded to the nearest thousandth.