title: Percentage changes in shares
body: <p>My data contains the closing prices of 10 shares of the S&amp;P 500 index.</p>
  <p>Data :</p>
  <pre><code>&gt; dput(head(StocksData))
  structure(list(ACE = c(56.86, 56.82, 56.63, 56.39, 55.97, 55.23
  ), AMD = c(8.47, 8.77, 8.91, 8.69, 8.83, 9.19), AFL = c(51.83, 
  50.88, 50.78, 50.5, 50.3, 49.65), APD = c(81.59, 80.38, 80.03, 
  79.61, 79.76, 79.77), AA = c(15.12, 15.81, 15.85, 15.66, 15.71, 
  15.78), ATI = c(53.54, 52.37, 52.53, 51.91, 51.32, 51.45), AGN = c(69.77, 
  69.53, 69.69, 69.98, 68.99, 68.75), ALL = c(29.32, 29.03, 28.99, 
  28.66, 28.47, 28.2), MO = c(20.09, 20, 20.07, 20.16, 20, 19.88
  ), AMZN = c(184.22, 185.01, 187.42, 185.86, 185.49, 184.68)), row.names = c(NA, 
  6L), class = &quot;data.frame&quot;)
  </code></pre>
  <p><em>For each of the 10 shares, i want to calculate their daily percentage changes.</em></p>
  <p>I am struggling with this because in this data i havent information about time , i havent info about year , month or days .
  Any thoughts on this would be helpful.</p>