What is an easy way to calculate YTD sales for last year for the same months that have sales this year? In the example below, I want a formula that will determine that we are 4 months into this year, and only add the first 4 months of last year so that we have a YTD comparison. In this example, the 272 is what I am looking for but I don't want to have to update the formula each month. Any help is appreciated!
[TABLE="width: 275"]
<tbody>[TR]
[TD][/TD]
[TD]Last Year[/TD]
[TD]This Year[/TD]
[/TR]
[TR]
[TD]January[/TD]
[TD]34[/TD]
[TD]45[/TD]
[/TR]
[TR]
[TD]February[/TD]
[TD]21[/TD]
[TD]36[/TD]
[/TR]
[TR]
[TD]March[/TD]
[TD]72[/TD]
[TD]45[/TD]
[/TR]
[TR]
[TD]April[/TD]
[TD]145[/TD]
[TD]21[/TD]
[/TR]
[TR]
[TD]May[/TD]
[TD]24[/TD]
[TD][/TD]
[/TR]
[TR]
[TD]June[/TD]
[TD]36[/TD]
[TD][/TD]
[/TR]
[TR]
[TD]July[/TD]
[TD]73[/TD]
[TD][/TD]
[/TR]
[TR]
[TD]August[/TD]
[TD]51[/TD]
[TD][/TD]
[/TR]
[TR]
[TD]September[/TD]
[TD]18[/TD]
[TD][/TD]
[/TR]
[TR]
[TD]October[/TD]
[TD]12[/TD]
[TD][/TD]
[/TR]
[TR]
[TD]November[/TD]
[TD]68[/TD]
[TD][/TD]
[/TR]
[TR]
[TD]December[/TD]
[TD]99[/TD]
[TD][/TD]
[/TR]
[TR]
[TD]TOTAL[/TD]
[TD]653[/TD]
[TD]147[/TD]
[/TR]
[TR]
[TD][/TD]
[TD][/TD]
[TD][/TD]
[/TR]
[TR]
[TD]Comparative[/TD]
[TD]272[/TD]
[TD]147[/TD]
[/TR]
</tbody>[/TABLE]
[TABLE="width: 275"]
<tbody>[TR]
[TD][/TD]
[TD]Last Year[/TD]
[TD]This Year[/TD]
[/TR]
[TR]
[TD]January[/TD]
[TD]34[/TD]
[TD]45[/TD]
[/TR]
[TR]
[TD]February[/TD]
[TD]21[/TD]
[TD]36[/TD]
[/TR]
[TR]
[TD]March[/TD]
[TD]72[/TD]
[TD]45[/TD]
[/TR]
[TR]
[TD]April[/TD]
[TD]145[/TD]
[TD]21[/TD]
[/TR]
[TR]
[TD]May[/TD]
[TD]24[/TD]
[TD][/TD]
[/TR]
[TR]
[TD]June[/TD]
[TD]36[/TD]
[TD][/TD]
[/TR]
[TR]
[TD]July[/TD]
[TD]73[/TD]
[TD][/TD]
[/TR]
[TR]
[TD]August[/TD]
[TD]51[/TD]
[TD][/TD]
[/TR]
[TR]
[TD]September[/TD]
[TD]18[/TD]
[TD][/TD]
[/TR]
[TR]
[TD]October[/TD]
[TD]12[/TD]
[TD][/TD]
[/TR]
[TR]
[TD]November[/TD]
[TD]68[/TD]
[TD][/TD]
[/TR]
[TR]
[TD]December[/TD]
[TD]99[/TD]
[TD][/TD]
[/TR]
[TR]
[TD]TOTAL[/TD]
[TD]653[/TD]
[TD]147[/TD]
[/TR]
[TR]
[TD][/TD]
[TD][/TD]
[TD][/TD]
[/TR]
[TR]
[TD]Comparative[/TD]
[TD]272[/TD]
[TD]147[/TD]
[/TR]
</tbody>[/TABLE]