title: Character 2 digit year conversion to year only
body: <p>Using R</p>
  
  <p>Got large clinical health data set to play with, but dates are weird</p>
  
  <p>Most problematic is <code>2digityear/halfyear</code>, as in <code>98/2</code>, meaning at some point in <code>1998</code> after <code>July 1</code></p>
  
  <p>I have split the column up into 2 character columns, e.g. <code>98</code> and <code>2</code> but now need to convert the <code>2</code> digit year character string into an actual year. </p>
  
  <p>I tried <code>as.Date(data$variable,format="%Y")</code> but not only did I get a conversion to <code>0098</code> as the year rather than <code>1998</code>, I also got todays month and year arbitrarily added (the actual data has no month or day). </p>
  
  <p>as in <code>0098-06-11</code></p>
  
  <p>How do I get just 1998 instead?</p>