Multiple Data Tables On A Single Graph?

I am trying to plot multiple tables on the same line chart in Excel 2007. I have a list of X and Y values for Table 1, Table 2, Table 3 etc.

However the size of the tables are not the same for each table. For example, Table 1 might have 200 X and Y values, Table 2 might have 175 X and Y values, Table 3 might have 105 X and Y values, etc.

So when I plot these data tables on one line chart the individual plots are off center. They should all be centered at 0.