bar_width should not be constrained to type 'int'. The API specifies
that if you want to automatically resize bars, chbh should be set to 'a'.
http://code.google.com/apis/chart/styles.html#bar_width
To automatically resize bars to fit the space available, specify
chbh=a,
<space between bars>,
<space between groups>
<space between bars> and <space between groups> should be specified in
pixels. These parameters are optional.
Thanks,
mb
RT for rt.cpan.org