title: Get percentage of a letter in python dictionary
body: <p>In the given dictionary, each key is a single lowercase letter and each value is the number of lowercase words that start with that letter. The str parameter is a single lowercase letter. Based on the values in the dictionary, return the percentage of words that start with that letter. </p>
  
  <p>Note: use floating-point division.</p>
  
  <pre><code>def get_letter_percentage(dictionary, s):
     '''(dict of {str : int}, str) -&gt; float'''
  
  # Start with a counter for the sum of the values.
  count = 0
  # And then look at the key and value of the dictionary
  for (key, value) in dictionary.items(): 
  </code></pre>
  
  <p>This is where I got stuck. I know I need to create a sum of the values in order to do a floating point division.</p>
  
  <pre><code># guessing it is something along these lines
  count = len(values) #??
  </code></pre>