To me, the chart-as-written says that the average time per level for people who reached only level 7 was ~18h, and for people who reached level 8 was ~36h? That

To me, the chart-as-written says that the average time per level for people who reached only level 7 was ~18h, and for people who reached level 8 was ~36h? That would mean level 8 took on average 8x36 - 7x18 = 162 hours to complete... Does it mean average total time, separated out by the max level reached (so, level 8 took at least 36-18=18 hours on average, but probably more)? Or is the level on the x axis mean "max level reached" for the number of people (dotted line), but "level" for the average time, so that it's just directly 36h average? It's further complicated because the clock kept ticking even when people took breaks to sleep and go to work, so I don't even know what to expect. To be fair, it has been ~360h since the competition began. Someone help me...