These graphs are a great example of why you should always label your axes. If you submitted these to a journal they'd be sent back for correction (assuming the editor didn't rage-toss your paper at first sight). If you included these in an undergraduate lab report they'd be docked marks heavily.

> These are some of the worst designed charts.

Especially because there was no label on the axes... and also no n size whatsoever and no information on how the question was asked and how the data is reported (averages? if yes it's completely useless data, averages are typically the worst kind of data you can extract).

Additionally the coloring choices are bad. The purple/blue split indicates relationships between items with the same color that don't exist. Combined with the confusing axis labels, my first interpretation of the plot was this was data comparing 2003 to 2015.

I figured it out eventually but at first I thought X was percent of people.

Also confusing is the "8 hours per day" subscript. Took me a while to figure out it actually is the Y axis labeling (but poorly placed and styled).

I thought it was years ... 1910, 1920 ...