Sue,
Percentage-formatted cells are based on 1 for 100%. It's only when you key
in the percentage that it's converted, for example you key 1.68%, and it
converts the actual value to .0168, and formats the cell for percentage.
When you change the cell formatting to %, it uses the existing value. Your
1.68 represents 168%. It will need to be scaled by .01. If you have a lot
of these, put .01 in a cell, Copy, then over the cells to be changed, do
Paste special - Multiply.
Another possible solution is to append the % with formatting. To do that,
Format - Cells - Number tab. Custom. After the existing code, put a %
symbol, in quotes, after the existing format code.
General"%"
0.00"%"
If there are any formulas that refer to the cells, they'll need to be scaled
by .01 (multiply by .01).