The data table displays the annual revenue of Starbucks, in billions of US $ for the corresponding year. Define t: year since 2000 and R: revenue in billions of US $.

Year	Revenue (billions of US $)
2003	4.10
2004	5.30
2005	6.40
2006	7.80
2007	9.40
2008	10.40
2009	9.80
2010	10.70
2011	11.70
2012	13.30
2013	14.90
2014	16.45
2015	19.16
2016	21.32
2017	22.39
2018	24.72
2019	26.51
2020	19.16