Checked checkbox background not working

I have used background color for checked checkbox through jQuery. My background color is adding only if i click any checkbox but not already clicked checkbox by default & i don't know why my class is not working on clicked checkbox by default.

$(document).ready(function() {
  /*checkbox-background*/
  $(".checkbox-primary").on("click", "input[type='checkbox']", function() {
    if ($(this).is(":checked")) {
      $(this).parent().addClass("fltr-chk-box-bg");
    } else {
      $(this).parent().removeClass("fltr-chk-box-bg");
    }
  });
  /*checkbox-background-ends*/
});

.checkbox {
  padding-left: 30px;
}

.checkbox>label {
  display: inline-block;
  position: relative;
  padding-left: 5px;
  color: #686868;
  padding-top: 2px;
  min-height: 25px;
  font-family: 'montserrat';
}

.checkbox>span {
  padding-right: 17px;
  padding-top: 3px;
  font-family: 'montserrat';
}
.checkbox input[type="checkbox"]:disabled+label::before {
  background-color: #eeeeee;
  cursor: not-allowed;
}

.checkbox.checkbox-circle label::before {
  border-radius: 50%;
}

.checkbox.checkbox-inline {
  margin-top: 0;
}

.fltr-chk-box-bg {
  background-color: #E3E7EA;
  color: #1E6C97;
}

.checkbox-primary input[type="checkbox"]:checked+label::before {
  background-color: #1E6C97;
  border-color: #428bca;
}

.checkbox-primary input[type="checkbox"]:checked+label::after {
  color: #fff;
}

.checkbox input[type="checkbox"]:checked+label+span {
  position: relative;
  z-index: 75456;
}

.checkbox input[type="checkbox"]:checked+label+span:before {
  content: '';
  position: absolute;
  top: 0;
  right: 0;
  border-bottom: 13px solid #CCD2D6;
  border-top: 11px solid #CCD2D6;
  border-right: 50px solid #CCD2D6;
  border-left: 6px solid transparent;
  z-index: -7523;
}

.fltr-panel-group {
  margin-bottom: 0px;
}

.fltr-panel {
  border-bottom: none;
}

.fltr-panel:last-child {
  border-bottom: 1px solid #ddd;
}

.fltr-panel-title>a {
  padding: 18px 8px 19px 8px;
  font-size: 1.21em;
  color: #2B3439;
  font-family: 'montserrat';
}

.panel-group .panel+.panel.fltr-panel {
  margin-top: 0px;
}

.panel-group.fltr-panel-group .panel-heading+.panel-collapse>.panel-body.fltr-panel-body {
  border-top: none;
  padding: 0px 5px 5px 5px;
}

.fltr-and-reset {
  padding-top: 14px;
  padding-bottom: 5px;
}

.fltr-and-reset a {
  vertical-align: middle;
  font-size: 0.78em;
}

.fltr-and-reset>.pull-right {
  font-size: 1.07em;
  color: #1E6C97;
  font-family: 'montserrat';
}

.fltr-and-reset>.text-left {
  font-size: 1.14em;
  color: #302F2F;
  line-height: 1.647;
  font-family: 'montserrat';
}

<!-- Latest compiled and minified CSS -->
<link rel="stylesheet" href="http://ift.tt/2apRjw3">

<!-- jQuery library -->
<script src="http://ift.tt/2nYZfvi"></script>

<!-- Latest compiled JavaScript -->
<script src="http://ift.tt/2aHTozy"></script>
<form>
  <div class="checkbox checkbox-primary">
    <input type="checkbox" value="" checked>
    <label>North America</label><span class="pull-right">75</span>
  </div>
  <div class="checkbox checkbox-primary">
    <input type="checkbox" value="" checked>
    <label>South America</label><span class="pull-right">98</span>
  </div>
  <div class="checkbox checkbox-primary">
    <input type="checkbox" value="">
    <label>North America</label><span class="pull-right">23</span>
  </div>
  <div class="checkbox checkbox-primary">
    <input type="checkbox" value="">
    <label>South Asia</label><span class="pull-right">47</span>
  </div>
  <div class="checkbox checkbox-primary">
    <input type="checkbox" value="">
    <label>South America</label><span class="pull-right">53</span>
  </div>
  <div class="checkbox checkbox-primary">
    <input type="checkbox" value="">
    <label>North America</label><span class="pull-right">55</span>
  </div>
  <div class="checkbox checkbox-primary">
    <input type="checkbox" value="">
    <label>South America</label><span class="pull-right">26</span>
  </div>
  <div class="checkbox checkbox-primary">
    <input type="checkbox" value="">
    <label>North America</label><span class="pull-right">23</span>
  </div>
  <div class="checkbox checkbox-primary">
    <input type="checkbox" value="">
    <label>South America</label><span class="pull-right">78</span>
  </div>
  <div class="checkbox checkbox-primary">
    <input type="checkbox" value="">
    <label>South America</label><span class="pull-right">90</span>
  </div>
  <div class="checkbox checkbox-primary">
    <input type="checkbox" value="">
    <label>North America</label><span class="pull-right">67</span>
  </div>
  <div class="checkbox checkbox-primary">
    <input type="checkbox" value="">
    <label>South America</label><span class="pull-right">88</span>
  </div>
</form>