what is the most home runs by an mlb team in a season before 2018

Before 2018, the Seattle Mariners hit the most home runs by a team in a season, with 264 home runs in 1997.

	TEAM	HR	SEASON	G	W%	W	L	AB	R	H	2B	3B	RBI	BB	HBP	SO	SB	CS	PA	TB	XBH	SH	SF	IBB	GIDP	AVG	OBP	SLG	OPS
1	Mariners	264	1997	162	.556	90	72	5,614	925	1,574	312	21	890	626	49	1,110	89	40	6,384	2,720	597	46	49	53	146	.280	.355	.485	.839
2	Rangers	260	2005	162	.488	79	83	5,716	865	1,528	311	29	834	495	48	1,112	67	15	6,300	2,677	600	9	32	20	123	.267	.329	.468	.798
3	Blue Jays	257	2010	162	.525	85	77	5,495	755	1,364	319	21	732	471	55	1,164	58	20	6,071	2,496	597	16	34	25	114	.248	.312	.454	.766
4	Orioles	257	1996	163	.543	88	74	5,689	949	1,557	299	29	914	645	61	915	76	40	6,493	2,685	585	31	67	49	134	.274	.350	.472	.822
5	Orioles	253	2016	162	.549	89	73	5,524	744	1,413	265	6	710	468	44	1,324	19	13	6,089	2,449	524	17	36	19	119	.256	.317	.443	.760
6	Astros	249	2000	162	.444	72	90	5,570	938	1,547	289	36	900	673	83	1,129	114	52	6,444	2,655	574	57	61	57	154	.278	.361	.477	.837
7	Rangers	246	2001	162	.451	73	89	5,685	890	1,566	326	23	844	548	75	1,093	97	32	6,388	2,676	595	25	55	27	131	.275	.344	.471	.815
8	Yankees	245	2012	162	.586	95	67	5,524	804	1,462	280	13	774	565	62	1,176	93	27	6,231	2,503	538	31	49	31	136	.265	.337	.453	.790
9	Mariners	245	1996	161	.528	85	76	5,668	993	1,625	343	19	954	670	75	1,052	90	39	6,517	2,741	607	46	58	57	121	.287	.366	.484	.850
10	Yankees	244	2009	162	.636	103	59	5,660	915	1,604	325	21	881	663	54	1,014	111	28	6,447	2,703	590	31	39	35	144	.283	.362	.478	.839
11	Blue Jays	244	2000	162	.512	83	79	5,677	861	1,562	328	21	826	526	60	1,026	89	34	6,326	2,664	593	29	34	32	130	.275	.341	.469	.810
12	Mariners	244	1999	162	.488	79	83	5,572	859	1,499	263	21	825	610	42	1,095	130	45	6,310	2,536	528	38	48	38	114	.269	.343	.455	.798
13	Athletics	243	1996	162	.481	78	84	5,630	861	1,492	283	21	823	640	58	1,114	58	35	6,402	2,546	547	35	39	36	134	.265	.344	.452	.796
14	White Sox	242	2004	162	.512	83	79	5,534	865	1,481	284	19	823	499	63	1,030	78	51	6,196	2,529	545	58	42	25	119	.268	.333	.457	.790
15	Yankees	242	2004	162	.623	101	61	5,527	897	1,483	281	20	863	670	80	982	84	33	6,364	2,530	543	37	50	40	157	.268	.353	.458	.811
16	Yankees	241	2017	162	.562	91	71	5,594	858	1,463	266	23	821	616	64	1,386	90	22	6,348	2,498	530	18	56	22	119	.262	.339	.447	.785
17	Yankees	240	1961	163	.673	109	53	5,559	827	1,461	194	40	781	543	35	785	28	18	6,239	2,455	474	57	45	45	120	.263	.330	.442	.771
18	Rangers	239	2003	162	.438	71	91	5,664	826	1,506	274	36	799	488	75	1,052	65	25	6,293	2,569	549	24	42	31	115	.266	.330	.454	.784
19	Athletics	239	2000	161	.565	91	70	5,560	947	1,501	281	23	908	750	52	1,159	40	15	6,432	2,545	543	26	44	32	147	.270	.360	.458	.817
20	Rockies	239	1997	162	.512	83	79	5,603	923	1,611	269	40	869	562	63	1,060	137	65	6,336	2,677	548	73	35	35	138	.288	.357	.478	.835
21	Astros	238	2017	162	.623	101	61	5,611	896	1,581	346	20	854	509	70	1,087	98	42	6,262	2,681	604	11	61	27	139	.282	.346	.478	.823
22	Red Sox	238	2003	162	.586	95	67	5,769	961	1,667	371	40	932	620	53	943	88	35	6,530	2,832	649	24	64	61	126	.289	.360	.491	.851
23	Rangers	237	2017	162	.481	78	84	5,430	799	1,326	255	21	756	544	81	1,493	113	44	6,121	2,334	513	27	39	18	110	.244	.320	.430	.750
24	White Sox	236	2006	162	.556	90	72	5,657	868	1,586	291	20	839	502	58	1,056	93	48	6,318	2,625	547	44	57	33	118	.280	.342	.464	.806
25	Angels	236	2000	162	.506	82	80	5,628	864	1,574	309	34	837	608	47	1,024	93	52	6,373	2,659	579	47	43	43	126	.280	.352	.472	.825