R-L21 reaches 20% in parts of northern Spain, as seen in the recent study of Martínez-Cruz et al. 2012, you have here the regions pertaining to Spain, and the percentage of R-L21 :
Southwestern Gipuzkoa, n = 13/57 = 22.81%
Roncal Valley, Navarra: n = 11/53 = 20.8 %
Alaba, n = 11/51 = 21.57%...