For CoffeeScript
Under xAxis, add
min: 0.05
max: 11
For Javascript,
Under xAxis, add
min: 0.05,
max: 11,
P.S. Adjust max
according to your needs.
DEMO: http://jsfiddle.net/ytfYe/2/
Ref: Highcharts Remove Space across the x-Axis
tag: bar column left right spacing remove