text: // SVG constants
  var SVG_WIDTH = 970;
  var SVG_HEIGHT = 400;
  
  // Line Chart Constants
  var MARGIN_TOP = 20;
  var MARGIN_LEFT = 55;
  var MARGIN_BOTTOM = 20;
  var MARGIN_RIGHT = 30; 
  
  // Dots Constants
  var DOT_RADIOUS = 7.5;
  var DOT_RADIOUS_INCREASE_HOVER = 2;