



 
Hi Jo, Change is measured as the new value minus the old value. If you want this as a proportion of the old value divide the change by the old value. To express this as a percentage you need to multiply by 100. For example from math 2009 to May 2010 the change was
As a proportion of the old value this is
Multiply this value by 100 to achieve the percentage change from May 2009 to May 2010. Penny  


Math Central is supported by the University of Regina and The Pacific Institute for the Mathematical Sciences. 