|  
                Year  
            |  
         
             Beginning Price  
            |  
         
             Ending Price  
            |  
         
             Gain or Loss 
            |  
         
             Percent Gain or Loss  
            |  
      
|  
           2007 
            |  
         
           16.94 
            |  
         
           16.53 
            |  
         
           -0.41 
            |  
         
           -2.42% 
            |  
      
|  
           2008 
            |  
         
           16.53 
            |  
         
           16.05 
            |  
         
           -0.48 
            |  
         
           -2.90% 
            |  
      
|  
           2009 
            |  
         
           16.05 
            |  
         
           14.41 
            |  
         
           -1.64 
            |  
         
           -10.22% 
            |  
      
|  
           2010 
            |  
         
           14.41 
            |  
         
           11.69 
            |  
         
           -2.72 
            |  
         
           -18.88% 
            |  
      
|  
           2011 
            |  
         
           11.69 
            |  
         
           13.01 
            |  
         
           1.32 
            |  
         
           11.29% 
            |  
      
|  
           2012 
            |  
         
           13.01 
            |  
         
           20.94 
            |  
         
           7.93 
            |  
         
           60.95% 
            |  
      
|  
           2013 
            |  
         
           20.94 
            |  
         
           27.45 
            |  
         
           6.51 
            |  
         
           31.09% 
            |  
      
|  
           2014 
            |  
         
           27.45 
            |  
         
           23.85 
            |  
         
           -3.60 
            |  
         
           -13.11% 
            |  
      
|  
           2015 
            |  
        
           23.85 
            |  
         
           25.02 
            |  
         
           1.17 
            |  
         
           4.91% 
            |  
      
|  
           2016 
            |  
        
           25.02 
            |  
         
           43.06 
            |  
         
           18.04 
            |  
         
           72.10% 
            |  
      
|  
           2017 
            |  
         
           43.06 
            |  
         
           42.21 
            |  
         
           -0.85 
            |  
         
           -1.97% 
            |  
      
|  
           2018 
            |  
         
           42.21 
            |  
         
           32.09 
            |  
         
           -10.12 
            |  
         
           -23.98% 
            |  
      
|  
           2019 
            |  
         
           32.09 
            |  
         
           44.23792** 
            |  
         
           12.1479 
            |  
         
           37.86% 
            |