title: Extract Yearly data of M4 competition
body: <p>I want to extract yearly data of M4 competition.
  For M3 and M1 data I extract "yearly" data using the following codes</p>
  
  <pre><code>library(Mcomp)
  yearly_m1 &lt;- subset(M1, "yearly")
  yearly_m3 &lt;- subset(M3, "yearly")
  </code></pre>
  
  <p>When I using following for the M4comp</p>
  
  <pre><code>library(M4comp)
  yearly_m4 &lt;- subset(M4, "yearly")
  </code></pre>
  
  <p>I get an error message. I am wondering how to extract yearly data of M4comp.</p>