What is the difference between the number of products manufactured by the company in the year 2009 and in 2008?

From the given graph, We can see that,
Number of products manufactured in 2009 = (52.5) × 1000
Number of products manufactured in 2008 = (48) × 1000
Required Difference = Number of products manufactured in 2009 - Number of products manufactured in 2008
Required Difference = ( 52.5 − 48 ) × 1000 = 4.5 x 1000 = 4500