Between the 1960 and 1968 seasons, the New York Mets had the worst winning percentage by a team, winning 34.8 percent of the time.

	TEAM	W%	W	L	G	AB	R	H	2B	3B	HR	RBI	BB	HBP	SO	SB	CS	PA	TB	XBH	SH	SF	IBB	GIDP	AVG	OBP	SLG	OPS
1	Mets	.348	394	737	1,136	38,126	3,740	8,886	1,263	221	707	3,448	3,005	288	7,306	349	308	42,090	12,712	2,191	438	233	298	840	.233	.292	.333	.626
2	Senators	.404	521	768	1,290	43,225	4,595	10,051	1,504	280	1,015	4,308	3,981	224	7,984	460	270	48,238	15,160	2,799	523	285	276	973	.233	.299	.351	.649
3	Athletics	.414	598	848	1,450	48,720	5,530	11,886	1,891	411	920	5,122	4,592	284	8,293	752	321	54,583	17,359	3,222	654	333	301	1,032	.244	.311	.356	.667
4	Astros	.419	474	658	1,135	38,081	3,868	9,077	1,357	278	605	3,568	3,339	271	6,300	433	281	42,503	12,805	2,240	564	248	396	855	.238	.303	.336	.639
5	Cubs	.446	643	798	1,449	49,191	5,767	12,158	1,910	417	1,225	5,400	4,425	311	8,770	547	392	54,863	18,577	3,552	584	352	541	1,010	.247	.311	.378	.689
6	Red Sox	.468	677	770	1,448	49,100	6,108	12,360	2,137	325	1,332	5,717	4,974	261	8,417	400	298	55,246	19,143	3,794	573	338	404	1,205	.252	.322	.390	.712
7	Angels	.475	614	679	1,294	43,143	4,799	10,380	1,563	282	934	4,451	4,071	271	7,957	464	321	48,447	15,309	2,779	649	313	338	901	.241	.308	.355	.663
8	Phillies	.483	696	744	1,442	48,727	5,675	12,102	1,877	417	1,064	5,252	4,308	330	8,880	505	381	54,447	18,005	3,358	748	334	534	1,004	.248	.312	.370	.681
9	Indians	.498	721	727	1,451	49,308	5,722	12,164	1,876	249	1,307	5,331	4,203	352	8,008	595	352	54,906	18,459	3,432	673	370	417	988	.247	.308	.374	.683
10	Braves	.526	758	684	1,446	49,279	6,281	12,602	1,912	311	1,478	5,881	4,435	318	8,045	585	373	54,967	19,570	3,701	577	358	547	1,109	.256	.319	.397	.716
11	Pirates	.527	760	681	1,445	49,957	6,060	13,344	1,942	510	1,025	5,642	3,841	256	8,100	530	361	55,056	19,381	3,477	636	366	616	1,159	.267	.320	.388	.708
12	Twins	.529	765	682	1,452	49,076	6,351	12,222	1,984	367	1,475	5,941	4,954	366	8,232	522	308	55,411	19,365	3,826	643	372	448	1,087	.249	.320	.395	.715
13	Reds	.535	771	669	1,442	49,619	6,271	12,894	2,206	381	1,264	5,862	4,047	322	8,243	694	411	54,898	19,654	3,851	556	354	595	1,023	.260	.318	.396	.714
14	White Sox	.541	784	666	1,452	48,905	5,753	12,058	1,843	365	934	5,317	4,756	409	7,209	854	438	55,239	17,433	3,142	778	391	409	1,011	.247	.316	.356	.673
15	Tigers	.547	792	657	1,454	49,007	6,384	12,126	1,784	363	1,522	5,978	5,321	364	8,204	527	276	55,665	19,202	3,669	627	346	401	1,084	.247	.324	.392	.715
16	Dodgers	.549	793	652	1,448	48,677	5,696	12,184	1,758	349	947	5,211	4,434	289	7,861	1,023	502	54,620	17,481	3,054	843	377	513	995	.250	.314	.359	.674
17	Cardinals	.553	797	643	1,444	49,626	6,134	12,989	2,023	444	1,020	5,680	4,038	299	7,898	786	409	54,935	18,960	3,487	622	350	500	954	.262	.319	.382	.701
18	Orioles	.554	802	645	1,449	48,763	5,977	12,003	1,994	300	1,307	5,593	4,843	302	8,446	550	301	55,001	18,518	3,601	706	387	445	1,106	.246	.316	.380	.696
19	Yankees	.558	807	639	1,454	49,257	6,114	12,078	1,752	297	1,502	5,744	4,690	257	7,998	440	250	55,165	18,930	3,551	615	346	434	1,007	.245	.312	.384	.696
20	Giants	.562	812	632	1,449	49,258	6,311	12,502	1,792	345	1,467	5,846	4,360	335	7,807	505	357	54,996	19,385	3,604	690	353	550	1,122	.254	.317	.394	.710