title: Tableau - Year Not being picked up as date
body: <p>I'm trying to create a time series / line graph in Tableau Public.  The imported excel file lists individual years as the variables/headers.  The values are numeric/counts.  The year is being picked up as categorical and so will only let me create bar charts ( and not line graphs).<br />
  How can I get the year to be picked up as a date in Tableau?</p>
  <p><a href="https://public.tableau.com/profile/kerr.mcintosh#!/vizhome/DateSeriesLineGraph/Sheet1" rel="nofollow noreferrer">https://public.tableau.com/profile/kerr.mcintosh#!/vizhome/DateSeriesLineGraph/Sheet1</a></p>
  <p><a href="https://i.stack.imgur.com/Zzm9Z.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/Zzm9Z.png" alt="Excel Spreadsheet Screenshot" /></a>
  <a href="https://i.stack.imgur.com/Zar57.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/Zar57.png" alt="Tableau Screenshot" /></a></p>