title: Count the number occurrence in List<Integer>
body: <p>I'm creating a small application that calculates a grade for a student. It takes two <code>List&lt;Integer&gt;</code> within a method. </p>
  
  <p>If my <code>list</code> contains 8 items, for example; <code>{52,62,65,65,72,72,75,75}</code> I want to find a way of counting through that <code>list</code> and finding the items that are within the same tenth (eg; 30, 40, 50, 60, 70). So this in case, 4 items will be within 70's and then be able to store it (known as a upper boundary). The aim of this is so that if 4 items are in a upper boundary, the overall student grade will be greater. </p>
  
  <p>My question is, how could I achieve this? I have seen that I could use some sort of <code>map</code> but I'm not sure if that will be the best way of achieve it. </p>