Have you repeated the same product, in serial yearly launches, in this below style ?
Launched March 2011 (for the first time) - generating $x sales
then, the same product,
Re-Launched March 2012 - generating $x sales
Re-Launched March 2013 - generating $x sales
Re-Launching March 2014 - generating $x sales
so the same exact product hat been launched 4 times, but once a year.
Have you done your product launches this way, (with that single product, launched every year)
How have your results been?
Do you find you get more sales each year?