From jens' website:
http://www.climbing-records.com/2016/07/hail-storm-slows-down-riders-on-arcalis.html
2016:10,0 km@7,0%---26:42---average speed 22.47 km/h(A.Yates-Froome-Quintana-Porte-D.Martin)
---29:40---average speed 20.22 km/h(Tom Dumoulin)
2009:10,0 km@7,0%---26:53---average speed 22.32 km/h(Alberto Contador)
---29:30---average speed 20.34 km/h(Brice Feillu)
2007:10,0 km@7,0%---27:08---average speed 22.11 km/h(Menchov-Evans-S.Sanchez-Beltran-Sastre-V.Efimkin-Piepoli)
2005:10,0 km@7,0%---26:30---average speed 22.64 km/h(Mancebo-Heras-Menchov)
2000:10,0 km@7,0%---26:14---average speed 22.87 km/h(Roberto Heras)
---26:49---average speed 22.37 km/h(Manolo Beltran)
---27:06---average speed 22.14 km/h(Pavel Tonkov)
---27:34---average speed 21.77 km/h(Roberto Laiseka)
Also:
1997:10,0 km@7,0%---24:55---average speed 24.08 km/h(Jan Ullrich)-RECORD