title: How to in calculate percentages in swift?
body: <p>I am creating an expense ios application. I am using a Progress View to display how much income the user has left. So for example, if the user puts $100 income, and $30 expense, I'd like the bar to be 70% full. How do I calculate this? </p>
  
  <p>I had originally put </p>
  
  <p><code>let fractionalProgress = Float(expenseFloat!)/Float(balanceFloat!)</code></p>
  
  <p>but this doesn't return the right value needed. </p>