(4) The graph below shows the number of smartphone users in the U.S. (in millions) from 2010 to 2021. (Note: Values for 2016-2021 were only projections.)* Graph showing the number of smartphone users in the U.S. (in millions) from 2010 to 2021. Y-axis represents the smartphone users in millions, ranging from 0 to 36,000. X-axis represents the year, ranging from 2010 to 2021. 2010 = 62.6 2011 = 92.8 2012 = 122 2013 = 144.5 2014 = 171 2015 = 189 2016 = 207.1 2017 = 222.9 2018 = 236.3 2019 = 247.5 2020 = 256.7 2021 = 264.3 (b) Describe any issues (or problems) with these data that might significantly affect the model's reliability