title: understanding the parameter "period" in Facebook API
body: <p>I've been working with graph api for a while, trying to get some insights for my page.
  The page have more than 30 likes. 
  I've had a problem that some values for daily insights were not showing, but they are present for the weekly. </p>
  
  <p>So I was trying to understand the weekly insight values.</p>
  
  <p>Example I had page_impressions_unique, which goes as following:</p>
  
  <pre><code>  "id": "893613667322766/insights/page_impressions_unique/week",
    "name": "page_impressions_unique",
    "period": "week",
    "values": [
      {
        "value": 37,
        "end_time": "2014-07-06T07:00:00+0000"
      },
      {
        "value": 38,
        "end_time": "2014-07-07T07:00:00+0000"
      },
      {
        "value": 40,
        "end_time": "2014-07-08T07:00:00+0000"
      },
      {
        "value": 40,
        "end_time": "2014-07-09T07:00:00+0000"
      },
      {
        "value": 58,
        "end_time": "2014-07-10T07:00:00+0000"
      },
      {
        "value": 67,
        "end_time": "2014-07-11T07:00:00+0000"
      },
      {
        "value": 41,
        "end_time": "2014-07-12T07:00:00+0000"
      },
      {
        "value": 33,
        "end_time": "2014-07-13T07:00:00+0000"
      },
      {
        "value": 32,
        "end_time": "2014-07-14T07:00:00+0000"
      },
      {
        "value": 31,
        "end_time": "2014-07-15T07:00:00+0000"
      },
      {
        "value": 31,
        "end_time": "2014-07-16T07:00:00+0000"
      }
    ],
  </code></pre>
  
  <p>Can anyone explain to me the following values? how is it growing before 12 and then the number decreases until 16?
  As how some values are not there for daily?</p>