Excel Chart does not have correct value

I have a line charts using a Date column
and two Value columns.
For 24 cells, everything works OK. With
the 25th entry the line turns sharply down
and shows an incorrect value!! This happens
even when I leave the entry empty!! When
I continue filling in data as a test the chart is
again correct.


Monday, May 08, 2006 36780.63
Tuesday, May 09, 2006 36948.93
Thursday, May 11, 2006 36496.29

Last point on line shows: Thursday, May 11, 2006 $29842.71
instead of $36496.29

What could cause this?
Many thanks
--
Occasionally stumped

Look at the data series. It will show the range of cells that are plotted in the chart. If the series is beyond your actual data it will do as you say. The data series can be edited.

The first time you make a chart causes the series to be recorded, then later on if you make your data range smaller the series will still be for the intial range so you got to edit it yourself.