Write a query that shows the change from sales in a year to year fashion as shown below:
SalesPersonID Salesyear SalesYear YearlyDifference
100 1999 2000 12433.00
100 2000 2001 58363.00
100 2001 2002 -105975.00
100 2002 2003 35899.00
100 2003 2004 58357.00
100 2004 2005 10200.00
100 2005 2006 11495.00