Show Difference as a Percentage

[V_Ernst]

I have volume data for 2007 and 2008. I am trying to show the difference
between the two numbers as a percentage.

Example: 2007 Volume was 400, 2008 Volume was 550. The difference is 150.
How do I express that 150 as a % of change or % difference

 

[John C]

A1: 400
B1: 550
C1: =IF(A1=0,"",(B1-A1)/A1)
format C1 as percentage.