title: Find max value for each year
body: <p>I have a question that is asking:</p>
  
  <p>-List the max sales for each year?</p>
  
  <p>I think I have the starter query but I can't figure out how to get all the years in my answer:</p>
  
  <pre><code>SELECT TO_CHAR(stockdate,'YYYY') AS year, sales
  FROM sample_newbooks
  WHERE sales = (SELECT MAX(sales) FROM sample_newbooks);
  </code></pre>
  
  <p>This query gives me the year with the max sales.  I need max sales for EACH year.  Thanks for your help!</p>