DA$14\mathrm{.}1$ Data visualization can be used to analyze trends in revenue.

Inditex is able to maintain a high and stable gross margin over this time period. Management should be quite pleased with this during a tough time in retail globally. Another measure of success, revenue per employee, can provide management with even more insight concerning its sales.

Inditex's net sales in millions and the number of employees from $2007$ through $2018$ are presented here.

$\backslash$table$[[$Year$,$Net Sales,$\backslash$table$[[$Number of$],[$Employees$]]],[2007,$$$9,435,79,517],[2008,10,407,89,112],[2009,11,084,92,301],[2010,12,527,100,138],[2011,13,793,109,512],[2012,15,946,120,314],[2013,16,724,128,313],[2014,18,117,137,054],[2015,20,900,152,854],[2016,23,311,162,450],[2017,25,336,171,839],[2018,26,145,174,386]]$

Use Excel or the visualization software of your or your instructor's choice to perform the following. There are four parts to this problem.

a$.$ Calculate revenue per employee for each year.

b$.$ Graph the revenue per employee over the $12-$year period using a clustered column chart with a trend line. Include axes labels, proper monetary formatting on the axes, and a descriptive chart title.

c$.$ What does the trend look like over time? Should management be concerned, cautiously optimistic, or pleased? Why? What factors may cause the changes in gross profit? Consider the gross profit example provided in the beginning of this problem in your response.

d$.$ What additional trends might be helpful for management to examine?