Between the 2004 and 2013 seasons, the Kansas City Royals had the lowest winning percentage by a team, winning 42.0 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	Royals	.420	681	939	1,620	55,765	6,991	14,807	2,917	368	1,259	6,621	4,375	542	10,261	983	404	61,538	22,237	4,544	412	444	303	1,363	.266	.323	.399	.721
2	Pirates	.436	705	913	1,618	54,933	6,628	13,903	2,837	314	1,412	6,344	4,646	638	11,873	781	356	61,286	21,604	4,563	640	429	367	1,225	.253	.316	.393	.710
3	Mariners	.443	718	902	1,620	55,651	6,570	14,189	2,650	239	1,422	6,216	4,478	451	10,938	998	358	61,357	21,583	4,311	384	393	371	1,187	.255	.314	.388	.701
4	Astros	.453	734	885	1,620	54,857	6,728	13,942	2,762	276	1,495	6,385	4,805	545	11,285	1,008	415	61,328	21,741	4,533	721	400	367	1,242	.254	.318	.396	.715
5	Orioles	.455	736	883	1,619	56,024	7,396	14,894	2,943	208	1,746	7,063	4,771	504	10,287	900	343	62,072	23,491	4,897	324	449	309	1,362	.266	.327	.419	.746
6	Nationals	.459	743	875	1,618	54,809	6,710	13,879	2,825	281	1,486	6,391	5,172	575	11,662	909	393	61,685	21,724	4,592	729	400	424	1,245	.253	.322	.396	.718
7	Rockies	.469	761	860	1,621	55,577	7,766	14,891	2,992	418	1,691	7,384	5,507	506	11,922	970	393	62,836	23,792	5,101	823	423	445	1,204	.268	.337	.428	.765
8	Diamondbacks	.473	767	853	1,620	55,143	7,099	14,046	3,031	370	1,636	6,801	5,419	484	11,963	839	363	62,052	22,725	5,037	567	439	468	1,187	.255	.324	.412	.737
9	Marlins	.475	769	850	1,619	55,113	6,991	14,139	2,876	334	1,559	6,628	5,112	610	12,143	972	373	61,928	22,360	4,769	683	410	452	1,173	.257	.324	.406	.730
10	Cubs	.477	772	846	1,618	55,486	7,076	14,431	3,009	293	1,697	6,720	4,821	499	11,256	762	348	61,793	23,117	4,999	614	373	383	1,273	.260	.323	.417	.739
11	Blue Jays	.489	791	828	1,619	55,521	7,494	14,404	3,055	270	1,806	7,141	5,094	570	10,676	829	325	61,923	23,417	5,131	271	467	277	1,302	.259	.326	.422	.747
12	Padres	.492	797	824	1,621	55,046	6,726	13,825	2,723	333	1,386	6,380	5,436	508	11,711	1,014	344	62,067	21,372	4,442	629	448	436	1,160	.251	.322	.388	.710
13	Indians	.495	802	818	1,620	55,605	7,669	14,608	3,127	256	1,686	7,323	5,553	689	11,755	851	370	62,656	23,305	5,069	345	464	347	1,251	.263	.335	.419	.754
14	Mets	.495	802	818	1,620	55,333	7,157	14,285	2,878	339	1,509	6,803	5,327	490	11,052	1,319	376	62,307	22,368	4,726	709	448	542	1,170	.258	.326	.404	.731
15	Brewers	.498	806	813	1,619	55,047	7,313	14,187	2,945	326	1,827	6,992	5,134	737	12,000	1,035	364	61,960	23,265	5,098	625	417	445	1,183	.258	.327	.423	.750
16	Reds	.500	810	810	1,621	55,299	7,371	14,148	2,882	226	1,880	7,034	5,574	625	12,176	895	354	62,612	23,122	4,988	711	403	475	1,147	.256	.329	.418	.747
17	Twins	.502	814	808	1,622	55,741	7,348	14,786	2,828	326	1,396	6,942	5,151	483	10,185	965	373	62,239	22,454	4,550	387	477	389	1,412	.265	.330	.403	.733
18	Rays	.502	814	806	1,620	54,916	7,418	14,088	2,820	355	1,730	7,080	5,538	565	11,796	1,418	493	61,827	22,808	4,905	320	488	299	1,131	.257	.328	.415	.744
19	Giants	.507	821	798	1,619	55,138	6,839	14,294	2,896	374	1,314	6,457	4,893	481	10,171	802	338	61,693	21,880	4,584	727	454	599	1,341	.259	.323	.397	.719
20	White Sox	.510	827	794	1,621	55,244	7,454	14,374	2,599	200	1,977	7,157	4,856	639	10,596	1,021	506	61,586	23,304	4,776	410	437	277	1,302	.260	.325	.422	.747
21	Tigers	.520	843	778	1,621	56,222	7,883	15,371	2,927	393	1,792	7,550	5,027	489	11,025	662	305	62,594	24,460	5,112	412	444	364	1,332	.273	.336	.435	.771
22	Athletics	.521	843	776	1,619	55,415	7,270	14,106	2,908	233	1,554	6,902	5,719	491	10,967	881	294	62,373	22,142	4,695	273	475	252	1,311	.255	.327	.400	.727
23	Dodgers	.527	853	766	1,619	55,106	7,078	14,465	2,699	309	1,407	6,734	5,327	527	10,682	1,067	428	62,093	22,003	4,415	701	432	527	1,303	.262	.331	.399	.730
24	Rangers	.530	859	762	1,621	56,268	8,241	15,252	3,104	296	2,015	7,859	4,996	507	11,042	1,013	344	62,612	24,993	5,415	357	484	331	1,214	.271	.333	.444	.778
25	Braves	.541	877	743	1,620	55,328	7,486	14,452	2,934	272	1,681	7,141	5,648	467	11,720	715	318	62,557	22,973	4,887	702	412	476	1,298	.261	.333	.415	.748