Solution:Surplus in 2009 = 47.8 - 47.2 = 0.6Surplus in 2010 = 50.7 - 49.5 = 1.2
Surplus in 2011 = 54.2 - 53.4 = 0.8
Surplus in 2012 = 57.3 - 54.5 = 2.8
Surplus in 2013 = 63.4 - 62.7 = 0.7
Total surplus = 0.6 + 1.2 + 0.8 + 2.8 + 0.7 = 6.1
Average surplus = 6.1/5 ⇒ 1.22