Age >= 37 and HR >= 37: Home Run Rate (AB/HR) percentages above the league. Ruth, Bonds, Aaron.

Who were the oldest proficient home run hitters through 2019? Who hit at least 37 home runs and was at least 37 years old? Below is a table with 23 seasons. Some players had multiple such seasons.

HR% is the percentage that a player's Home Run rate (AB/HR; lower is better) is above the league Home Run rate that season.

Eight had HR% at least 70%, actually, at least 73%.

Maximum. Minimum.  Age is generally season minus birth year.

Sorted by HR%:

Year	L	Team	First	Last	bats	Age	HR	HR%	BA%	BAplayer	HRratePlay	AB	H	BB	BA_L	HRrate_L	BA1	throws	Lname
1932	AL	NYA	Babe	Ruth	L	37	41	81.85%	23.37%	.3414	11.15	457	156	130	.27670	61.429	No	L	Ruth
2001	NL	SFN	Barry	Bonds	L	37	73	78.15%	25.39%	.3277	6.52	476	156	177	.26137	29.844	No	L	Bonds
1971	NL	ATL	Hank	Aaron	R	37	47	77.96%	30.01%	.3273	10.53	495	162	71	.25173	47.790	No	R	Aaron
1973	NL	ATL	Hank	Aaron	R	39	40	77.02%	18.29%	.3010	9.80	392	118	68	.25447	42.637	No	R	Aaron
2002	NL	SFN	Barry	Bonds	L	38	46	74.10%	42.66%	.3697	8.76	403	149	198	.25916	33.832	Yes	L	Bonds
2003	NL	SFN	Barry	Bonds	L	39	45	73.46%	30.40%	.3410	8.67	390	133	148	.26153	32.654	No	L	Bonds
2004	NL	SFN	Barry	Bonds	L	40	45	73.38%	37.83%	.3619	8.29	373	135	232	.26259	31.139	Yes	L	Bonds
1957	AL	BOS	Ted	Williams	L	39	38	73.04%	52.25%	.3881	11.05	420	163	119	.25491	41.003	Yes	R	Williams
1954	NL	CHN	Hank	Sauer	R	37	41	66.38%	8.80%	.2885	12.68	520	150	70	.26512	37.726	No	R	Sauer
1985	AL	DET	Darrell	Evans	L	38	40	64.41%	-5.25%	.2475	12.63	505	125	85	.26123	35.472	No	R	Evans
1998	NL	ATL	Andres	Galarraga	R	37	44	63.52%	16.35%	.3045	12.61	555	169	63	.26170	34.581	No	R	Galarraga
2006	AL	OAK	Frank	Thomas	R	38	39	61.25%	-1.61%	.2704	11.95	466	126	81	.27481	30.832	No	R	Thomas
2002	AL	TEX	Rafael	Palmeiro	L	38	43	59.78%	3.45%	.2729	12.70	546	149	104	.26378	31.570	No	L	Palmeiro
2001	AL	TEX	Rafael	Palmeiro	L	37	47	59.06%	2.42%	.2733	12.77	600	164	101	.26687	31.179	No	L	Palmeiro
1985	AL	CHW	Carlton	Fisk	R	37	37	58.63%	-9.06%	.2376	14.68	543	129	52	.26123	35.472	No	R	Fisk
2015	AL	BOS	David	Ortiz	L	39	37	54.62%	6.77%	.2727	14.27	528	144	77	.25543	31.449	No	L	Ortiz
2019	AL	MIN	Nelson	Cruz	R	39	41	53.91%	22.67%	.3106	11.07	454	141	56	.25317	24.024	No	R	Cruz
2003	AL	TEX	Rafael	Palmeiro	L	39	38	52.89%	-2.63%	.2602	14.76	561	146	84	.26728	31.337	No	L	Palmeiro
2018	AL	SEA	Nelson	Cruz	R	38	37	50.82%	2.82%	.2563	14.03	519	133	55	.24924	28.521	No	R	Cruz
2004	NL	CHN	Moises	Alou	R	38	39	50.51%	11.52%	.2928	15.41	601	176	68	.26259	31.139	No	R	Alou
2016	AL	BOS	David	Ortiz	L	40	38	49.68%	22.53%	.3147	14.13	537	169	80	.25684	28.082	No	L	Ortiz
2000	AL	SEA	Edgar	Martinez	R	37	37	48.58%	17.44%	.3237	15.03	556	180	96	.27566	29.221	No	R	Martinez
2017	AL	SEA	Nelson	Cruz	R	37	39	45.57%	12.55%	.2878	14.26	556	160	70	.25568	26.194	No	R	Cruz
Year	L	Team	First	Last	bats	Age	HR	HR%	BA%	BAplayer	HRratePlay	AB	H	BB	BA_L	HRrate_L	BA1	throws	Lname
2019				Maximum			73	81.85%	52.25%	.3881	15.41	601	180	232	.27670	61.429
1932				Minimum			37	45.57%	-9.06%	.2376	6.52	373	118	52	.24924	24.024

Babe Ruth numero uno but only for age 37, the minimum, and only that one season.

BA1: leading in Batting Average (BA): only Bonds (twice) and Williams.

Here again are those seasons of at least 70% HR%:

Year	L	Team	First	Last	bats	Age	HR	HR%
1932	AL	NYA	Babe	Ruth	L	37	41	81.85%
2001	NL	SFN	Barry	Bonds	L	37	73	78.15%
1971	NL	ATL	Hank	Aaron	R	37	47	77.96%
1973	NL	ATL	Hank	Aaron	R	39	40	77.02%
2002	NL	SFN	Barry	Bonds	L	38	46	74.10%
2003	NL	SFN	Barry	Bonds	L	39	45	73.46%
2004	NL	SFN	Barry	Bonds	L	40	45	73.38%
1957	AL	BOS	Ted	Williams	L	39	38	73.04%

Barry Bonds and Hank Aaron and dominate. That's an interesting combination. We assume that Bonds got an assist from performance enhancing drugs (PED). How did Aaron do it?

Bonds and Aaron: Home Run Rate (AB/HR) percentages above the league. Comparison by age. Friday, February 18, 2022

1990-2009: Home Run Rate (AB/HR) percentages above the league. Mark McGwire and/or Barry Bonds #1, PED not withstanding. Thursday, February 10, 2022

Batting Average and Home Run Rate percentages above the league 1950-2019. Williams and Schmidt lead. Saturday, February 5, 2022

1. Ted Williams, Home Run King? Yes, using AB/HR. Wednesday, December 18, 2019