I get your point too joeri. 2 of those years in Hamburg, Rafa didn't play. By the way, sorry for the off topic here but that mandatory business for the super 9 is not working very well. I've noticed this season that only 10 out of the top 30 players played all 9 masters ( Djoko, Berd, Tipsy, Raonic, Cilic, Dolgo, Kohl, Seppi, F. Mayer and Melzer) . Murray, Tsonga, Gasquet, Monaco and Simon played only 8 (and apart from Gasquet, M-C was not the one they skipped). Ferrer, Delpo, Almagro, Isner, Wawrinka, Nishikori, Querrey, Verdasco and Youzhny played only 7 (and for a number of those M-C was not even one of the 2 skipped), Federer played 6 and of course Nadal and Fish played less but not of their own willing +Haas.
They try to force the top guns but the players still do pretty much as they like .