on october 11th 2007, TJ posted a wondeful example of Low-Level gfx
code showing monthly and yearly returns. Today I notice that for the
yearly calculation it uses close at end of the first trading day of
first year and compare it to the first trading day of the 2nd year. In
my opinion this is an incorrect calculation of yearly change. It
excludes the movement in prices of the first trading day of first year
and includes the price movement of the first trading day of next year.
Looking at the code it seems to me that it makes the same mistake is
made in calculating monthly returns.
