For mid-week entertainment, this full-page ad appeared in the Wall Street Journal recently:
The vertical axis says "% NYSE of All Market Share Volume". The time-line is from July 05 to beyond July 08. The text in the black box is "Matched Market Share: July 11, 2008".
When it's so obvious, it's probably not obvious. The big story is off the chart: what happened to the other 50% of the volume over the years?
Faced with this, one reaches for the pie chart (... almost).
Small add (8/21/2008):