title: Get unusual colnanme in data.frame
body: <p>Here is my code,  </p>
  
  <pre><code>x&lt;-c(70, 82, 91, 76, 84, 94, 72, 76, 74, 67, 70, 45, 69, 86, 75,
      84, 63, 93, 87, 67, 71, 83, 90, 88, 58, 69, 91, 74, 80, 79,  
      75, 88, 87, 50, 80, 84, 94, 72, 85, 71, 81, 74, 75, 81, 75, 57,
      78, 78, 61, 60)                 
  y&lt;-table(cut(x, breaks=c(0,60,70,80,90,100),include.lowest=TRUE,right=FALSE)) 
  z&lt;-cbind(y,prop=prop.table(y)*100)  
  z
  </code></pre>
  
  <p>i can get the table: </p>
  
  <pre><code>          y prop  
  [0,60)    4    8  
  [60,70)   7   14  
  [70,80)  18   36  
  [80,90)  15   30  
  [90,100]  6   12  
  </code></pre>
  
  <p>if i want to get the table such as </p>
  
  <pre><code>          y prop%  
  [0,60)    4    8
  [60,70)   7   14
  [70,80)  18   36
  [80,90)  15   30
  [90,100]  6   12
  </code></pre>
  
  <p>how can i do?</p>