highest career win percentage by a pitcher with 300 wins

Lefty Grove has the best career win percentage when winning 300+ games, at .680.

Interpreted as:

highest career win percentage by a pitcher with 300 or more wins

	NAME	W	W%	L	G	GS	ERA	SO	CG	SHO	SV	IP	H	ER	R	HR	BB	HBP	GF	IBB	TBF	WP	K/9	BB/9	K/BB	HR/9	K%	BB%	WHIP	BABIP	RA	ERA-	FIP	FIP-	H/9	PRAA
1	Lefty Grove L. Grove	300	.680	141	616	457	3.06	2,266	298	35	54	3940.2	3,849	1,339	1,594	162	1,187	42	123		16,622	51	5.18	2.71	1.91	0.37	13.6	7.1	1.28	.284	3.64	68	3.36	76	8.79	462.8
2	Christy Mathewson C. Mathewson	373	.665	188	636	552	2.13	2,507	435	79	30	4788.2	4,219	1,135	1,620	89	848	59	73		18,913	115	4.71	1.59	2.96	0.17	13.3	4.5	1.06	.268	3.04	75	2.26	76	7.93	363
3	Roger Clemens R. Clemens	354	.658	184	709	707	3.12	4,672	118	46	0	4916.2	4,185	1,707	1,885	363	1,580	159	0	63	20,240	143	8.55	2.89	2.96	0.66	23.1	7.8	1.17	.284	3.45	70	3.08	71	7.66	680.4
4	John Clarkson J. Clarkson	328	.648	178	531	518	2.81	1,978	485	37	5	4536.1	4,295	1,417	2,384	159	1,191	80	12		19,146	182	3.92	2.36	1.66	0.32	10.3	6.2	1.21	.263	4.73	75	3.35	88	8.52	289.8
5	Randy Johnson R. Johnson	303	.646	166	618	603	3.29	4,875	100	37	2	4135.1	3,346	1,513	1,703	411	1,497	190	7	37	17,067	109	10.61	3.26	3.26	0.89	28.6	8.8	1.17	.291	3.71	75	3.18	73	7.28	554.3
6	Grover Alexander G. Alexander	373	.642	208	696	600	2.56	2,198	436	90	32	5190.0	4,868	1,476	1,852	165	951	70	81		20,893	38	3.81	1.65	2.31	0.29	10.5	4.6	1.12	.269	3.21	73	2.88	81	8.44	359.1
7	Kid Nichols K. Nichols	361	.634	208	621	562	2.96	1,881	532	48	17	5067.1	4,929	1,664	2,480	156	1,272	129	56		21,082	169	3.34	2.26	1.48	0.28	8.9	6.0	1.22	.271	4.40	73	3.48	85	8.75	377.8
8	Eddie Plank E. Plank	326	.627	194	623	529	2.35	2,246	410	69	23	4495.2	3,958	1,174	1,566	42	1,072	190	77		17,803	88	4.50	2.15	2.10	0.08	12.6	6.0	1.12	.275	3.14	81	2.45	86	7.92	195.2
9	Cy Young C. Young	511	.618	316	906	815	2.63	2,803	749	76	17	7356.0	7,092	2,147	3,167	138	1,217	161	84		29,565	156	3.43	1.49	2.30	0.17	9.5	4.1	1.13	.275	3.87	74	2.84	79	8.68	620
10	Old Hoss Radbourn O. Hoss Radbourn	309	.614	194	527	502	2.68	1,830	488	35	3	4527.1	4,328	1,347	2,273	118	875	54	24		18,918	214	3.64	1.74	2.09	0.23	9.7	4.6	1.15	.262	4.52	82	3.15	95	8.60	51
11	Greg Maddux G. Maddux	355	.610	227	744	740	3.16	3,371	109	35	0	5008.1	4,726	1,756	1,981	353	999	137	3	177	20,421	70	6.06	1.80	3.37	0.63	16.5	4.9	1.14	.281	3.56	76	3.25	78	8.49	519.5
12	Tim Keefe T. Keefe	342	.603	225	600	594	2.63	2,564	554	39	2	5049.2	4,438	1,474	2,470	75	1,233	83	7		20,941	240	4.57	2.20	2.08	0.13	12.2	5.9	1.12	.257	4.40	79	2.92	87	7.91	239.2
13	Tom Seaver T. Seaver	311	.603	205	656	647	2.86	3,640	231	61	1	4783.0	3,971	1,521	1,674	380	1,390	76	6	116	19,369	126	6.85	2.62	2.62	0.72	18.8	7.2	1.12	.259	3.15	79	3.03	85	7.47	286.1
14	Tom Glavine T. Glavine	305	.600	203	682	682	3.54	2,607	56	25	0	4413.1	4,298	1,734	1,900	356	1,500	66	0	145	18,604	65	5.32	3.06	1.74	0.73	14.0	8.1	1.31	.280	3.87	86	3.94	94	8.76	120.1
15	Walter Johnson W. Johnson	417	.599	279	802	666	2.17	3,509	531	110	34	5914.1	4,913	1,424	1,902	97	1,363	205	127		23,405	154	5.34	2.07	2.57	0.15	15.0	5.8	1.06	.264	2.89	68	2.42	76	7.48	472.8
16	Warren Spahn W. Spahn	363	.597	245	750	665	3.09	2,583	382	63	28	5243.2	4,830	1,798	2,016	434	1,434	42	67	60	21,547	81	4.43	2.46	1.80	0.74	12.0	6.7	1.19	.258	3.46	84	3.44	94	8.29	124.4
17	Mickey Welch M. Welch	307	.594	210	565	549	2.71	1,850	525	41	4	4802.0	4,588	1,447	2,556	106	1,297	52	16		20,308	274	3.47	2.43	1.43	0.20	9.1	6.4	1.23	.264	4.79	88	3.28	103	8.60	-55.7
18	Steve Carlton S. Carlton	329	.574	244	741	709	3.22	4,136	254	55	2	5217.2	4,672	1,864	2,130	414	1,833	53	13	150	21,683	183	7.13	3.16	2.26	0.71	19.1	8.5	1.25	.279	3.67	87	3.14	86	8.06	271.5
19	Don Sutton D. Sutton	324	.559	256	774	756	3.26	3,574	178	58	5	5282.1	4,692	1,914	2,104	472	1,343	82	12	102	21,631	112	6.09	2.29	2.66	0.80	16.5	6.2	1.14	.261	3.58	92	3.23	90	7.99	181.2
20	Early Wynn E. Wynn	300	.551	244	691	611	3.54	2,334	289	49	16	4564.0	4,291	1,796	2,037	338	1,775	64	67	36	19,408	51	4.60	3.50	1.31	0.67	12.0	9.1	1.33	.265	4.02	94	3.64	97	8.46	56.4
21	Gaylord Perry G. Perry	314	.542	265	777	690	3.11	3,534	303	53	10	5350.0	4,938	1,846	2,128	399	1,379	108	33	164	21,953	160	5.95	2.32	2.56	0.67	16.1	6.3	1.18	.275	3.58	85	3.06	85	8.31	312.9
22	Pud Galvin P. Galvin	361	.540	308	697	681	2.87	1,799	639	57	1	5941.1	6,352	1,895	3,315	121	744	54	18		25,160	220	2.73	1.13	2.42	0.18	7.2	3.0	1.19	.278	5.02	94	2.97	95	9.62	94.5
23	Phil Niekro P. Niekro	318	.537	274	864	716	3.35	3,342	245	45	29	5404.0	5,044	2,012	2,337	482	1,809	123	83	86	22,677	226	5.57	3.01	1.85	0.80	14.7	8.0	1.27	.270	3.89	87	3.61	95	8.40	116.1
24	Nolan Ryan N. Ryan	324	.526	292	807	773	3.19	5,714	222	61	3	5386.0	3,923	1,911	2,178	321	2,795	158	13	78	22,575	277	9.55	4.67	2.04	0.54	25.3	12.4	1.25	.265	3.64	90	2.96	83	6.56	370.2