Between the 2001 and 2010 seasons, the Kansas City Royals had the worst winning percentage by a team, winning 40.9 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	.409	662	958	1,620	55,654	7,239	14,756	2,893	374	1,341	6,820	4,513	590	9,920	905	425	61,653	22,420	4,608	437	459	283	1,349	.265	.324	.403	.727
2	Pirates	.414	669	948	1,617	54,923	6,784	14,044	2,840	297	1,440	6,480	4,777	692	11,145	771	369	61,465	21,798	4,577	648	425	400	1,207	.256	.321	.397	.718
3	Orioles	.426	690	928	1,620	55,887	7,328	14,853	2,952	240	1,582	6,977	4,820	561	9,611	1,014	397	62,101	23,031	4,774	364	469	308	1,323	.266	.328	.412	.740
4	Nationals	.440	713	906	1,619	54,612	6,815	13,924	2,922	296	1,414	6,487	5,334	580	10,987	929	446	61,719	21,680	4,632	773	420	508	1,334	.255	.326	.397	.722
5	Rays	.446	721	897	1,618	55,326	7,374	14,395	2,907	359	1,609	7,034	5,139	566	11,370	1,415	488	61,844	22,847	4,875	346	467	310	1,111	.260	.327	.413	.740
6	Tigers	.451	731	889	1,620	55,857	7,464	14,830	2,816	433	1,700	7,125	4,736	512	10,812	815	410	61,990	23,612	4,949	430	455	303	1,247	.265	.326	.423	.749
7	Brewers	.460	745	874	1,619	55,020	7,257	14,112	2,939	296	1,827	6,942	5,315	718	12,239	900	369	62,058	23,124	5,062	593	412	457	1,246	.256	.328	.420	.748
8	Reds	.467	757	863	1,621	55,273	7,407	14,162	2,888	221	1,897	7,074	5,548	649	12,101	943	382	62,564	23,183	5,006	702	392	451	1,171	.256	.329	.419	.749
9	Rockies	.475	770	851	1,621	55,577	8,121	15,068	3,066	423	1,766	7,712	5,702	556	11,508	938	423	63,072	24,278	5,255	794	443	467	1,238	.271	.342	.437	.779
10	Padres	.483	783	838	1,621	55,218	6,993	14,067	2,731	309	1,453	6,650	5,719	482	11,252	847	347	62,466	21,775	4,493	583	464	435	1,251	.255	.328	.394	.722
11	Diamondbacks	.485	785	835	1,620	55,257	7,303	14,237	2,999	392	1,694	6,997	5,591	491	11,380	790	338	62,400	23,102	5,085	602	459	509	1,198	.258	.329	.418	.747
12	Indians	.491	795	825	1,620	55,701	7,888	14,773	3,126	272	1,787	7,540	5,527	701	11,254	752	387	62,797	23,804	5,185	400	468	362	1,296	.265	.337	.427	.764
13	Rangers	.491	795	825	1,620	56,401	8,407	15,244	3,133	295	2,144	8,030	5,171	562	11,142	854	300	62,955	25,399	5,572	334	487	329	1,209	.270	.335	.450	.785
14	Mets	.494	800	818	1,618	55,020	7,144	14,220	2,793	311	1,563	6,774	5,261	528	10,474	1,219	389	61,989	22,324	4,667	732	448	550	1,236	.258	.327	.406	.732
15	Mariners	.498	807	813	1,620	55,988	7,307	15,000	2,792	275	1,436	6,912	4,877	519	10,027	1,139	397	62,273	22,650	4,503	412	477	446	1,253	.268	.330	.405	.734
16	Blue Jays	.498	807	812	1,619	55,843	7,797	14,802	3,199	297	1,809	7,443	5,124	646	10,435	727	289	62,346	24,022	5,305	240	493	305	1,339	.265	.331	.430	.761
17	Marlins	.502	812	807	1,619	55,247	7,436	14,550	3,019	340	1,647	7,046	5,234	653	11,692	1,066	449	62,249	23,190	5,006	678	437	493	1,178	.263	.332	.420	.752
18	Cubs	.505	817	801	1,618	55,449	7,414	14,595	2,991	288	1,806	7,079	5,164	490	11,093	739	336	62,269	23,580	5,085	744	422	455	1,289	.263	.329	.425	.754
19	Astros	.516	836	783	1,620	55,009	7,321	14,324	2,861	295	1,672	6,982	5,242	618	10,481	876	381	62,046	22,791	4,828	751	426	450	1,304	.260	.329	.414	.744
20	White Sox	.524	850	771	1,621	55,114	7,899	14,576	2,774	213	2,115	7,587	5,103	615	10,063	1,001	487	61,746	24,121	5,102	462	452	274	1,312	.264	.331	.438	.769
21	Giants	.526	850	767	1,618	55,107	7,259	14,424	2,932	362	1,596	6,891	5,327	516	9,905	716	322	62,144	22,868	4,890	741	453	729	1,353	.262	.330	.415	.745
22	Dodgers	.528	856	764	1,620	55,246	7,193	14,445	2,722	322	1,521	6,847	5,226	554	10,280	1,024	431	62,117	22,374	4,565	672	419	510	1,309	.261	.329	.405	.734
23	Athletics	.544	880	739	1,619	55,543	7,597	14,375	2,990	221	1,639	7,238	5,892	566	10,235	730	254	62,742	22,724	4,850	258	483	320	1,364	.259	.333	.409	.743
24	Phillies	.545	882	737	1,619	55,791	8,042	14,679	3,043	342	1,910	7,662	6,128	651	11,335	1,138	291	63,622	24,136	5,295	598	454	639	1,141	.263	.340	.433	.773
25	Twins	.548	888	733	1,621	55,925	7,754	15,234	3,008	375	1,497	7,317	5,152	524	9,837	1,005	437	62,502	23,483	4,880	395	506	425	1,429	.272	.337	.420	.757