title: Growth over Years in SQL
body: <p>I have a table with <code>member_id</code>, <code>joined</code> (as in time joined) and I'm trying to figure out how to find percent growth between years.
  I have</p>
  <pre class="lang-sql prettyprint-override"><code>SELECT YEAR(joined) AS JoinedYear, COUNT(member_id) AS Members
  FROM grp_member 
  GROUP BY YEAR(joined) 
  ORDER BY JoinedYear asc;  
  </code></pre>
  <p>this shows the number of people joining per year but need help finding growth using subqueries.</p>