Since this variable's purpose is to count the number of aircraft in each state, it makes
sense to make it an integer, with an initial value of zero and set it to reset its value for
each state (remember stateGroup is a report group we created earlier, dividing the
report by states). Now that we have created the report variable, we can use it as the
value expression for our chart. Next, we right-click on the 3-D bar chart and select
the Chart properties tab and then Chart data tab.