While reading the newest print version of the German LinuxMagazin i found an interview with Mark Shuttleworth, which made me partly wonder. There he says:

“Bei vielen Sachen, die einen großen Einfluss auf Systeme wie den Kernel, X.org oder Open Office haben, übernehmen wir die Führungsrolle, wir stellen die Pakete und viele gelangen so zu Debian. Also sind wir in vielen Fällen der Upstream von Debian.” (english: On many things, which do have a great influence on systems like kernel, X.org or Open Office, we take the leadership role, we supply the packages and many of those getting into Debian this way. Therefore we are the upstream of Debian in many cases.)

I know of certain packages, like python, gcc, apt and maybe X.org, which are mainly maintained by Ubuntu developers. But is this really true: Is Ubuntu really upstream of many Debian packages?

Can someone please enlighten me, and give me some statistics where Ubuntu is upstream of Debian, and where Debian is upstream of Ubuntu? I would really like to know the facts.