I think around 2012.
I definitively recall seeing him that year and was struck how different he looked, after being out of public view for some time. Coincidentally, this was the same year Obama was reported to say:
Don't underestimate Joe's ability to fuck things up
Also in 2012, Putin halted adoptions of Russian children to the United States and Trump tweeted his 'Fast Trial, Death Penalty' for PEDOPHILES
https://nationalfile.com/flashback-trump-recommends-fast-trial-death-penalty-for-pedophiles/
I think around 2012.
I definitively recall seeing him that year and was struck how different he looked, after being out of public view for some time. Coincidentally, this was the same year Obama was reported to say:
Don't underestimate Joe's ability to fuck things up