I always wondered why but just recently I discovered a trick while browsing on the phone. I was using Puffin browser and accidentally hovered/dragged the User score/# of votes thing over to the other side with my finger and discovered some "hidden" votes to the left (see screenshot below) I couldn't do this on the laptop though. The question is why don't the lower ratings show up in the chart for most dramas/movies (just because less people rated them it's not included in the chart then?)
"OR its more about how many decimal it show, you know 156/31520=0.004%. the stat prob doesnt bother to show more than 2 decimal after coma." Spot on! The problem is you can't even put .004% on a chart. It's not enough to be clickable.