<html>
  <head>
    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
  </head>
  <body text="#000000" bgcolor="#FFFFFF">
    <p>Actually building:buildyear is of much more widespread use than
      building:start_date:</p>
    <ul>
      <li><a class="moz-txt-link-freetext" href="https://taginfo.openstreetmap.org/keys/?key=building%3Abuildyear">https://taginfo.openstreetmap.org/keys/?key=building%3Abuildyear</a>
        -> 2051 objects</li>
      <li><a class="moz-txt-link-freetext" href="https://taginfo.openstreetmap.org/keys/?key=building%3Astart_date">https://taginfo.openstreetmap.org/keys/?key=building%3Astart_date</a>
        -> 163 objects</li>
    </ul>
    <p>that's a 12.6:1 proportion...</p>
    <p>The key is documented in the IndoorOSM proposal [1] and in a wiki
      page of which I fail to understand the meaning [2].<br>
    </p>
    <p>Sergio</p>
    <p><br>
    </p>
    <p>[1]
      <a class="moz-txt-link-freetext" href="https://wiki.openstreetmap.org/wiki/Proposed_features/IndoorOSM">https://wiki.openstreetmap.org/wiki/Proposed_features/IndoorOSM</a></p>
    <p>[2] <a class="moz-txt-link-freetext" href="https://wiki.openstreetmap.org/wiki/Item:Q2952">https://wiki.openstreetmap.org/wiki/Item:Q2952</a><br>
    </p>
    <div class="moz-cite-prefix"><br>
    </div>
    <div class="moz-cite-prefix">On 2019-02-16 10:39, Anton Klim wrote:<br>
    </div>
    <blockquote type="cite"
      cite="mid:0BFBE3D2-30D0-47CD-937E-0BEAB2138C6F@gmail.com">
      <pre class="moz-quote-pre" wrap="">I believe there was an (failed? Undocumented?) attempt to make building:buildyear a thing, but haven’t seen it used for a while. 
</pre>
    </blockquote>
  </body>
</html>