If I haven’t missed any, these are all the stages on which Contador has attacked, and the result (relative to Froome):
Stage 8. Finished same time
Stage 11. Lost 23 seconds (including time bonus).
Stage 12. Gained 42 seconds.
Stage 14. Lost 6 seconds.
Stage 15: Lost 40 seconds.
Stage 17: Gained 1:24 (including time bonus).
Stage 18: Finished same time.
Stage 19: Finished same time.
Net: :57 gained
Also interesting to note the GC just since the second rest day:
Contador
Froome :25
Kelderman :31
Zakarin :46
Nibali :51
Poels 1:50
Lopez 2:50
Woods 3:32
Aru 3:34
Chaves 9:43
Stage 8. Finished same time
Stage 11. Lost 23 seconds (including time bonus).
Stage 12. Gained 42 seconds.
Stage 14. Lost 6 seconds.
Stage 15: Lost 40 seconds.
Stage 17: Gained 1:24 (including time bonus).
Stage 18: Finished same time.
Stage 19: Finished same time.
Net: :57 gained
Also interesting to note the GC just since the second rest day:
Contador
Froome :25
Kelderman :31
Zakarin :46
Nibali :51
Poels 1:50
Lopez 2:50
Woods 3:32
Aru 3:34
Chaves 9:43