a food-store chain has the following record for yearly sales volume(in hundreds of thousands of dollars for the past 9 years.

a food-store chain has the following record for yearly sales volume(in hundreds of thousands of dollars for the past 9 years.

year          sales volume

2003         7

2004         15

2005          10

2006          5

2007           11

2008          17

2009          12

2010           8

2011            17

Find the cyclical component and estimate the period to the cycle