You need to add a formula to your category names on your spreadsheet, similiar to the example I have posted.
<colgroup><col style="WIDTH: 30px; FONT-WEIGHT: bold"><col style="WIDTH: 76px"><col style="WIDTH: 44px"></colgroup><tbody>
[TD="bgcolor: #cacaca, align: center"]1[/TD]
[TD="bgcolor: #c0c0c0, align: center"]Month[/TD]
[TD="bgcolor: #c0c0c0, align: center"]Data[/TD]
[TD="bgcolor: #cacaca, align: center"]2[/TD]
[TD="align: center"]January[/TD]
[TD="align: right"]908[/TD]
[TD="bgcolor: #cacaca, align: center"]3[/TD]
[TD="align: center"]February[/TD]
[TD="align: right"]290[/TD]
[TD="bgcolor: #cacaca, align: center"]4[/TD]
[TD="align: center"]March[/TD]
[TD="align: right"]160[/TD]
[TD="bgcolor: #cacaca, align: center"]5[/TD]
[TD="align: center"]April[/TD]
[TD="align: right"]289[/TD]
[TD="bgcolor: #cacaca, align: center"]6[/TD]
[TD="align: right"]0[/TD]
[TD="bgcolor: #cacaca, align: center"]7[/TD]
[TD="align: center"]June[/TD]
[TD="align: right"]949[/TD]
[TD="bgcolor: #cacaca, align: center"]8[/TD]
[TD="align: center"]July[/TD]
[TD="align: right"]242[/TD]
[TD="bgcolor: #cacaca, align: center"]9[/TD]
[TD="align: center"]August[/TD]
[TD="align: right"]802[/TD]
[TD="bgcolor: #cacaca, align: center"]10[/TD]
[TD="align: right"]0[/TD]
[TD="bgcolor: #cacaca, align: center"]11[/TD]
[TD="align: center"]October[/TD]
[TD="align: right"]266[/TD]
[TD="bgcolor: #cacaca, align: center"]12[/TD]
[TD="align: center"]November[/TD]
[TD="align: right"]705[/TD]
[TD="bgcolor: #cacaca, align: center"]13[/TD]
[TD="align: center"]December[/TD]
[TD="align: right"]239[/TD]
</tbody>