Examples 19 and 20 presented graphs showing the total student enrollment at a U.S. university between 2004 and 2012 and the data for STEM major enrollment during that same time period. The data are repeated here.

a. Construct a graph for only STEM major enrollments over this period. Describe the trend in these enrollment counts.
b. Find the percentage of enrolled students each year who are STEM majors, and construct a time plot of the percentages.
c. Summarize what the graphs constructed in parts a and b tell you that you could not learn from Figures 2.18 and 2.19 in Examples 19 and 20.

Enrollment at the U.S. University ear 2004 2005 2006 2007 2008 2009 2010 2011 2012 Total Students 29 404 29,693 30,009 30,912 31,288 32,317 32.941 33.878 33,405 STEM Majors 2,003 1,906 1,871 1.815 1.856 1,832 1825 1,897 1.854