Put the data in a 2 row (1st row = year, 2nd = data) x (however many you need) column format with the first column being "year" (r1) then "data" (r2) - highlight the entire data then click the graph button and it should work straight away.
i.e.
If you have the data as above and it only has intermediate years then you need to double click the X axis and, choose the "Scale" tab from the pop-up and ensure the "number of categories between X axis labels" and "number of categories between tick marks" is set to 1.
You need the data in a simple table with years going across row 1 and the data in the cells below & legend going down column A - doesn't sound like you do.
You might find this page helpful as well, especially the sections on dialogue boxes, where you tell Excel which data you want plotted and on what axis.