Mid 2014 had the strongest top10 ever name wise.
Big4, Stan, Delpo, Ferrer, Berdych, Nishikori, Raonic.
stats usually support 2012 as strongest followed by 2015 and 2009+11-14 period and some peak with 1982.
strongest era is 11-16 that is actually noiles 1st era.
top5 since 2003:
03: roddick, fed, ferrero, agassi, coria
...fed era...
04: fed, roddick, hewitt, safin, moya
05: fed, rafa, roddick, hewitt, denko
06: fed, rafa, denko, blake, ljuba (feds record 15495 points)
07: fed, rafa, nole, denko, ferrer
08: rafa, fed, nole, muzza, denko
09: fed, rafa, nole, muzza, potro
...rafas transitions-era year....
10: rafa, fed, nole, muzza, sod
...no1es 1st era...
11: no1e, rafa, fed, muzza, ferrer
12: no1e, fed, muzza, rafa, ferrer
13: rafa, nole, ferrer, muzza, potro, (fed)
14: no1e, fed, rafa, wawa, nishi, (muzza)
15: no1e, muzza, fed, wawa, rafa
RG16: no1e, muzza, fed, rafa, wawa (no1s record 16950 points)
...
16: muzza, nole, raonic, wawa, nishi
....fedals renesanse....
17: rafa, fed, dimitrov, zver, thiem
RG18: rafa, fed, zver, potro, cilic
....noles 2ns era since W18....
18: no1e, rafa, fed, zver, potro
19: rafa, nole, fed, thiem, med
20: no1e, rafa, thiem, med, fed
21: no1e, med, zver, tsitsi, rublev
22: raz, rafa, ruud, tsitsi, no1e*
23: nole, raz, med, sinner, rublev
....sinneraz era....
24: sinner, zver, raz, fritz, med
25: raz, sinner, zver, nole, FAA