The first graph shows that DM3 is still the most popular team level by far: one third of all rounds took place on DM3(1). The second most popular level was DM2; selected as the map in 23% of the cases. E1M2 is almost matched in popularity by DM6, whereas E3M7 was only played in less then one tenth of the cases.
Although DM6 was only played in 16% of the rounds, it accounts for 26% of the total frags made(2). The rest of the maps are represented in the score count pretty much in accordance with their relative frequency.
This is easily explained by looking at the next figure, which gives the overal average of the winners and loser scores on all maps.
The average score of the losing team is presented by a rectangle on top of that of the winning team. The total height then becomes the average total map score, and that is obviously much higher for DM6 then for all the other maps. Games on DM3 typically result in the lowest scores, with only 180 frags for the winning team.
Notes:
(1) The percentages are maps played, not the total amount of games (which consist of multiple maps) the map was played in.
(2) frags here are final scores of the team, i.e. suicides and teamfrags are taken into account implicitely.
