title: Obtaining the start and end dates from a single column of data
body: <p>I'm trying to find the Start and End date of a product's sales period from a column of data that is a dummy variable for sale. Here is a proxy of the type of data that I am working with:
  <a href="https://i.stack.imgur.com/dnXoA.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/dnXoA.png" alt="enter image description here" /></a></p>
  <p>The result I am looking for is:</p>
  <p><a href="https://i.stack.imgur.com/wzS0K.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/wzS0K.png" alt="enter image description here" /></a></p>
  <p>The actual data set I am working on is much larger than this and does not necessarily look at just 2010-01 to 2011-12.</p>
  <p>Thank you!</p>