We define x as a year between 2008 and 2013 and y as the total number of smartphones sold that year, in millions. The table shows values of x and corresponding y
values.

Year ( x ) and number of smartphones in millions ( y )
2008 - 3.7
2009 - 17.3
2010 - 42.2
2011 - 90
2012 - 125
2013 - 153.2

In which year were 90 million smartphones sold?