I guess it's a case of relative sales given the year. With IBIY being released at end of 2004, the majority of it's sales were split over 2004/5 and probably amounted to roughly 125-130K (at a guess)
That figure would've placed it at about #40 or better in the Year-end chart for 2004 or in the lower 30's for 2005 Year-end chart
Comparing this to the Year-end for 2013 the #30 track sold 437K and the #40 track sold 365K
Even in the YTD for 2004 IBIY was #63 with 81K sold, YTD for 2013 had the #63 track selling 284K