On Thu, 10 Jan 2008, in microsoft.public.excel.charting,
said:

"Jon Peltier" wrote:
I should add, change the Y axis scale so it starts at zero, otherwise
interpretation of the column values will be severely distorted. Excel
autoscales the axis to start at 94, which makes the 2008 value of 101 appear
to be less than half of 2007's 110.

Thanks John.

I will give this a try.

I noticed that the annual averages are close to 100 for most years,
making them a little hard to tell apart if the y axis goes down to zero.

Jon is quite right that a zero origin y axis is essential for column
charts, and all visualisations that depend on a perception of area from
the origin. But have you considered abandoning the idea of bars for the
annual average, and using lines instead? If you format your data like
this...

Annual Weekly
31/12/2003
31/12/2003
31/12/2003 104
31/12/2004 104
31/12/2004
31/12/2004 107
31/12/2005 107
31/12/2005
31/12/2005 108
31/12/2006 108
31/12/2006
31/12/2006 110
31/12/2007 110
31/12/2007
31/12/2007 101
01/01/2008 101 100
07/01/2008 101 101
14/01/2008 101 102
31/12/2008 101
31/12/2008
31/12/2008

....then the chart wizard should automatically detect the dates and apply
a Time-scale x axis type, producing the correct graph type if you select
"Line Chart" in the wizard. This would let you have the y axis start
around 90, giving you a good separation of annual averages, without
misleading anyone (lines and symbols don't need a zero origin because
they don't depend on an area, only a difference in position).

And if you still want to see columns, you can quickly select the annual
series, choose "Chart Type.. Area", and columns will appear (they're
areas really, but they look like columns :-)

--
Del Cotter
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