Already addressed in a post above ->So after AO 2012 he lost 3 in a row in slams, and many overall. Nadal has declined massively in tiebreaks over the years.
Nadal's TB stats only started taking a dive from 2014 onwards (when prime ended)
He was at 65.7% TBs won (157 /239 ) from 2005 to 2013 - which is pretty high
58.5% (96/164) from 2014-current