10. 1998 Home Run rates: McGwire breaks HR record ... year after expansion.

Babe Ruth held the season home run record from 1919 through 1960. Then Roger Maris held it 1961-1997. The next record breaker wouldn't hold nearly that long.

AB: At Bats

HR: Home Runs
MLB: Major League Baseball: both American League and National League
Home Run Rate: AB/HR (lower is better)
N: number of MLB teams that season
Top home run hitters: N hitters with the most HR, plus any ties at the bottom
Home Run Rate MLB: for N hitters: total AB / total HR
Home Run Rate hitters: AB/HR
Dif: Home Run Rate hitter - Home Run Rate MLB
PctDif: Dif/Home Run Rate MLB
HR#: rank among N hitters for HR
PctDif#: rank among N hitters for PctDif

Hitters are ranked by relative position: 1, 2, 3, ... Ties would have the same number and then rank number would resume. For example, if four players are tied at third place: 1, 2, 3, 3, 3, 3, 7, 8, ...

Mark McGwire took a run at the record as a rookie in 1987 finishing with 49. In 1997 McGwire hit 58, most in MLB, but not leading either league as he was traded from Oakland (34) to St. Louis (24). Two new teams had been added in 1993 and two more in 1997, bringing the total to the 30 teams that exist in 2019.

In 1998 the top home run hitters were 31 batters who hit at least 31 home runs. McGwire's PctDif was 49.17% better than that group and way better than number two, Sammy Sosa, who also broke the 1961 home run record but with way more At Bats (AB) than McGwire. Finishing 15th in PctDif was Barry Bonds.

qryHomeRunsTopNyearPctDif

yearID	nameFirst	nameLast	PctDif	PctDif#	HR#	HR	AB	P_AB/HR	Group_ AB/HR	Dif	franchID	teamID	lgID
1998	Mark	McGwire	49.17%	1	1	70	509	7.271429	14.30	7.03	STL	SLN	NL
1998	Sammy	Sosa	31.89%	2	2	66	643	9.742424	14.30	4.56	CHC	CHN	NL
1998	Ken	Griffey	20.98%	3	3	56	633	11.30357	14.30	3.00	SEA	SEA	AL
1998	Greg	Vaughn	19.89%	4	4	50	573	11.46	14.30	2.84	SDP	SDN	NL
1998	Albert	Belle	13.11%	5	5	49	609	12.42857	14.30	1.88	CHW	CHA	AL
1998	Andres	Galarraga	11.82%	6	10	44	555	12.61364	14.30	1.69	ATL	ATL	NL
1998	Jose	Canseco	11.40%	7	6	46	583	12.67391	14.30	1.63	TOR	TOR	AL
1998	Manny	Ramirez	11.29%	8	8	45	571	12.68889	14.30	1.62	CLE	CLE	AL
1998	Henry	Rodriguez	6.41%	9	27	31	415	13.3871	14.30	0.92	CHC	CHN	NL
1998	Juan	Gonzalez	5.86%	10	8	45	606	13.46667	14.30	0.84	TEX	TEX	AL
1998	Carlos	Delgado	2.50%	11	14	38	530	13.94737	14.30	0.36	TOR	TOR	AL
1998	Vinny	Castilla	1.98%	12	6	46	645	14.02174	14.30	0.28	COL	COL	NL
1998	Javy	Lopez	-0.54%	13	21	34	489	14.38235	14.30	-0.08	ATL	ATL	NL
1998	Rafael	Palmeiro	-0.64%	14	11	43	619	14.39535	14.30	-0.09	BAL	BAL	AL
1998	Barry	Bonds	-4.30%	15	18	37	552	14.91892	14.30	-0.61	SFG	SFN	NL
1998	Mo	Vaughn	-6.44%	16	13	40	609	15.225	14.30	-0.92	BOS	BOS	AL
1998	Moises	Alou	-7.44%	17	14	38	584	15.36842	14.30	-1.06	HOU	HOU	NL
1998	Jeff	Bagwell	-11.03%	18	21	34	540	15.88235	14.30	-1.58	HOU	HOU	NL
1998	Jeromy	Burnitz	-12.04%	19	14	38	609	16.02632	14.30	-1.72	MIL	MIL	NL
1998	Alex	Rodriguez	-14.18%	20	12	42	686	16.33333	14.30	-2.03	SEA	SEA	AL
1998	Vladimir	Guerrero	-14.61%	21	14	38	623	16.39474	14.30	-2.09	WSN	MON	NL
1998	Dean	Palmer	-17.61%	22	21	34	572	16.82353	14.30	-2.52	KCR	KCA	AL
1998	Jeff	Kent	-18.62%	23	27	31	526	16.96774	14.30	-2.66	SFG	SFN	NL
1998	Ray	Lankford	-20.20%	24	27	31	533	17.19355	14.30	-2.89	STL	SLN	NL
1998	Nomar	Garciaparra	-20.64%	25	19	35	604	17.25714	14.30	-2.95	BOS	BOS	AL
1998	Mike	Piazza	-22.56%	26	26	32	561	17.53125	14.30	-3.23			NL
1998	Chipper	Jones	-23.57%	27	21	34	601	17.67647	14.30	-3.37	ATL	ATL	NL
1998	Tony	Clark	-23.78%	28	21	34	602	17.70588	14.30	-3.40	DET	DET	AL
1998	Shawn	Green	-25.83%	29	19	35	630	18	14.30	-3.70	TOR	TOR	AL
1998	Andruw	Jones	-31.25%	30	27	31	582	18.77419	14.30	-4.47	ATL	ATL	NL
1998	Scott	Rolen	-35.53%	31	27	31	601	19.3871	14.30	-5.08	PHI	PHI	NL