Take a look at the wiki documentation for
the xaxis categories.
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You will need to give the right labels, and do not expect all output to start with January. For example, if you start a new database in June, then you would use xAxis_categories = 'Jun', 'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec'. **It is up to you to provide the right labels for the data you're expecting. **