Year-over-year percentage of change

[lstreet]

I am trying to find the percentage of change in customers. This wouldn't be a
problem with the formula =IF(C35=0,D35,(D35-C35)/C35). However, the problem
arises when one of the cells is 0. So in this case let's say D35 is 35 and
C35 is 0. This returns a percent of increase of 3500%. Here is a snapshot of
the data I am having problems with

Thru 0908
2005 AVG 2006 AVG 2007 AVG 2008 AVG
(prod introduced)
0 0 35 36

I am then using all of the percentages of change found to determine and
average change for the 4 years. The 3500% throughs the calcuation off.

Any suggestions?

 

[Gary''s Student]

=IF(C35=0,"",(D35-C35)/C35)

This leaves the cell blank. If you later use the =AVERAGE() function, you
will find that AVERAGE ignores these blanks

 

[lstreet]

Nice, this seeems to work nicely. One more thing however is that there are
times that it returns the dreaded #DIV/0!. How can I avoid this?

 

[Glenn]

Can't see any way that this formula could return that error. You are dividing
by C35 only if C35 IS NOT equal to zero.