Today we reach the 2010s, specifically the years from 2011 until 2019 which are now often called the 'Sky Era'. Sky dominated until the Tour de France 2019 with 7 wins in 8 years, before the Vuelta 2019 marked a change of the guard.
The peak level in this decade was more or less consistent, but the densitity of riders 'capable of climbing' did increase in the second half of the decade.
2011| Joaquim Rodriguez | 83 (0): 6.4 W/kg for 32:07 on Collet d'Allevard
2012| Joaquim Rodriguez | 80 (-10): 7.75 W/kg for 6:46 on Mirador de Ezaro
2013| Chris Horner | 81 (-3): 6.23 W/kg for 42:15 on Angliru
2014 | Nairo Quintana | 83 (-7): 6.23 W/kg for 52:39 on Grappa ITT
........... | Fabio Aru | 83 (-7): 6.23 W/kg for 52:40 on Grappa ITT
2015 | Nairo Quintana | 83 (+3): 6.14 W/kg for 41:20 on Terminillo
2016 | Richie Porte | 81 (+3): 6.33 W/kg for 30:20 on Finhaut Emosson
........... | Nairo Qintana | 81 (-2): 6.56 W/kg for 25:43 on Covadonga
2017 | Richie Porte | 88 (-11): 7.84 W/kg for 7:41 on Willunga
2018 | Gonzalo Najar | 87 (+6): 6.25 W/kg for 36:58 on Colorado (very uncertain)
2019 | Miguel Angel Lopez | 85 (+7): 6.53 W/kg for 22:39 on Javalambre
Notes:
1) Rodriguez was in amazing form in the 2011 Dauphine with 2 stage victories, rare for someone coming out of the Giro.
2) Horner makes the list with his legendary performance on the Angliru.
3) 2014 had more good performances then the years prior, perhaps a surprise for Quintana and Aru to top the list.
4) Richie Porte in 2016 and especially in 2017 was in really good overall shape. His performance on Leysin in 2017 Tour of Romandie could potentially be even better than Willunga Hill.
5) Najar in San Juan put on a display of force on Alto de Colorado. This calculation is quite uncertain (tailwind + shallow gradients).
6) Lopez on Javalmbre was a really strong performance, dropping Roglic and young Pogacar. Even in the 2023 Vuelta with the Jumbo sweep they did not even come close to this time.