Assuming you mean
this image , this is how I read it:
The width of a civ's bar at any given time is their
relative score. For example at the start of the game, each would have (say) 0 points for citizens and 1 point for territory. So they are all the same. If after 10 turns one civ has two cities and the others only have one, then the civ with two cities would have a bar ~twice as wide as the others'.
In ~1430 the Americans were destroyed. If someone wins by conquest, at the end the whole width of the bar would be their colour.
The graph does not show absolute score.
The reason the American's have a score of 81 in the top-right is explained in the bottom-right:
Your overall score is the average of your {absolute} scores on each turn