The file P$03\_40.$xIsx contains monthly data on the number of vehicles crossing the border from Mexico into four southwestern states.

a$.$ Restructure this data set on a new sheet so that there are three long columns: Month, State, and Crossings. Essentially, you should stack the original columns B through $E$ on top of one another to get the Crossings column, and you should also indicate which state each row corresponds to in the State column. The Month column should have four replicas of the original Month column.

b$.$ Create a pivot table and corresponding pivot table chart based on the restructured data. It should break down the average of Crossings by Year and State. Comment on any patterns you see in the chart.