There have been only 6 years where there have been summits on K2 since 1998. The other 6 years there were no summits. The years where there were no summits were as follows: 1998, 1999, 2002, 2003, 2005, and 2009. Out of all the 8000m mountains this is the highest number of years in this period where there were no summits.
In between these years was the highest summit year for K2 which was in 2004. This was the year which was the 50th anniversary of the Italian first ascent of K2 in 1954. The number who climbed it in 2004 was 51 summits.
At one time there were reports that Jorge Egocheaga had made the summit in 2009. But he later said that he had stopped 12m from the summit. As yet there have been no photos provided to show exactly where he got to.
Within these 12 years was also the terrible 2008 tragedy on K2 which claimed the lives of 11 climbers.