If you take aside his earliest two years in the format, 2004 and 2005, when he played only three Tests as a particularly raw customer and averaged 6.75 and 17.50 respectively, he is best judged in the period since 2006 when he became a settled member of the Proteas side.
Amla earned his maiden century - the first of 23 thus far - against New Zealand at Newlands that year, and averaged 29.09 from six appearances as he began an impressive, almost unrelenting upward climb in performance terms.
There were very few “blowout” years for him all the way to the end of 2014, as the list below will show, including a truly stellar 2010 (average 78.06) and 2012 (70.93, among his heavy scores then being the maiden triple century by a South African against England at The Oval).
The now 32-year-old kept his touch splendidly through 2014 as well, when he averaged 63.63 from eight Tests.
But that also only highlights how unusually miserable 2015 - now mercifully wrapped up after the 241-run defeat under his charge to England at Kingsmead - has been for the bearded maestro.
Also having taken part in eight Tests during the latest calendar year, Amla could only post 251 runs at 22.81; a quite violent comedown from his 2014 and for many years before it.
He managed no centuries, a concept alien to him since 2005, and notched up a solitary half-ton (63) achieved right at the outset of 2015 against West Indies in Cape Town.
As 2016 launches imminently for his Proteas team in the second Test against England at Newlands from Saturday, Amla is only just clinging to his magnificent, 50-plus overall Test average, commanded for some time.
It stands at 50.05 from 89 Tests (6,907 runs, 151 innings), so there is a real danger of it dipping below 50 in the signature Test over New Year if he struggles for major runs again.
But if he can put his woes behind him at Newlands, there is the incentive of compiling 93 runs in the contest to reach 7,000 Test runs, which would make him the fourth-fastest South African to the landmark.
Already there are Graeme Smith (achieved in 148 knocks) and Jacques Kallis and AB de Villiers (151 innings each).
Amla will certainly be happy to put 2015 behind him, given this sequence of personal scores since it began: 63 and 38 not out (West Indies, Cape Town), 13 (Bangladesh, Dhaka), 43 and 0 (India, Mohali), 7 (India, Bangalore), 1 and 39 (India, Nagpur), 3 and 25 (India, Delhi), and 7 and 12 (England, Durban).
His many admirers will be hoping 2016 sees him confirm the permanence of class ...
Here is the list of Amla’s calendar-year runs in Tests:
2004: 27 at average 6.75 (two Tests)
2005: 35 at 17.50 (one Test)
2006: 320 at 29.09 (six Tests)
2007: 660 at 44.00 (nine Tests)
2008: 1 161 at 52.77 (15 Tests)
2009: 384 at 34.90 (six Tests)
2010: 1,249 at 78.06 (11 Tests)
2011: 423 at 47.00 (five Tests)
2012: 1 064 at 70.93 (10 Tests)
2013: 633 at 57.54 (eight Tests)
2014: 700 at 63.63 (eight Tests)
2015: 251 at 22.81 (eight Tests)
*Follow our chief writer on Twitter: @RobHouwing