highest win-loss percentage by a pitcher before turning 25 with at least 75 games started

Walter Johnson has the most career pitcher wins - pitcher loss percentage by a player younger than 25 when starting 75+ games, with 109.58.

Interpreted as:

highest win-loss percentage by a pitcher before turning 25 years old with at least 75 games started

	NAME	W-L%	GS	W	L%	L	W%	G	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	H/9
1	Walter Johnson W. Johnson	109.58	182	110	.424	81	.576	211	0.08	1,156	158	31	6	1614.2	1,256		487	12	360	66	28			74	6.44	2.01	3.21	0.07		5.7	1.00	.261	2.71	7.00
2	Bob Feller B. Feller	106.66	175	107	.335	54	.665	205	3.18	1,233	117	16	10	1448.1	1,149	512	569	58	815	26	24		6,187	46	7.66	5.06	1.51	0.36	19.9	13.2	1.36	.269	3.54	7.14
3	Joe Wood J. Wood	101.67	141	102	.333	51	.667	193	0.59	933	111	25	6	1257.2	992		453	9	369	51	45			40	6.68	2.64	2.53	0.06		7.3	1.08	.266	3.24	7.10
4	Dwight Gooden D. Gooden	99.72	175	100	.281	39	.719	177	2.64	1,168	52	19	1	1291.0	1,053	379	423	65	379	18	1	17	5,215	26	8.14	2.64	3.08	0.45	22.4	7.3	1.11	.276	2.95	7.34
5	Bert Blyleven B. Blyleven	94.53	213	95	.472	85	.528	216	2.78	1,327	97	24	0	1611.1	1,416	498	566	114	403	39	2	23	6,534	31	7.41	2.25	3.29	0.64	20.3	6.2	1.13	.280	3.16	7.91
6	Hal Newhouser H. Newhouser	93.57	173	94	.430	71	.570	231	2.86	895	94	19	10	1376.1	1,165	438	537	38	673	6	43		5,852	29	5.85	4.40	1.33	0.25	15.3	11.5	1.34	.266	3.51	7.62
7	Wes Ferrell W. Ferrell	90.65	131	91	.355	50	.645	167	3.58	476	97	7	12	1118.1	1,150	445	538	46	457	6	28		4,878	14	3.83	3.68	1.04	0.37	9.8	9.4	1.44	.284	4.33	9.25
8	Denny McLain D. McLain	89.65	164	90	.348	48	.652	171	3.11	917	70	17	1	1176.2	933	406	449	151	355	15	2	9	4,737	17	7.01	2.72	2.58	1.15	19.4	7.5	1.09	.237	3.43	7.14
9	Babe Ruth B. Ruth	88.66	143	89	.341	46	.659	158	2.19	495	105	17	4	1190.1	934		376	9	433	29	11			27	3.74	3.27	1.14	0.07		9.0	1.15	.239	2.84	7.06
10	Pete Donohue P. Donohue	82.61	146	83	.390	53	.610	173	3.29	344	88	10	8	1157.2	1,236		518	26	222	26	22		4,858	7	2.67	1.73	1.55	0.20	7.1	4.6	1.26	.285	4.03	9.61
11	Larry Dierker L. Dierker	82.55	191	83	.450	68	.550	205	3.14	965	66	11	1	1409.0	1,268	491	556	109	386	22	5	29	5,797	64	6.16	2.47	2.50	0.70	16.6	6.7	1.17	.269	3.55	8.10
12	Waite Hoyt W. Hoyt	81.59	143	82	.410	57	.590	195	3.43	401	82	10	8	1243.1	1,303	474	550	36	362	22	41		5,274	14	2.90	2.62	1.11	0.26	7.6	6.9	1.34	.285	3.98	9.43
13	Milt Pappas M. Pappas	81.58	167	82	.423	60	.577	198	3.41	678	60	16	4	1186.0	1,046	450	495	100	437	28	21	22	4,936	54	5.15	3.32	1.55	0.76	13.7	8.9	1.25	.256	3.76	7.94
14	Don Gullett D. Gullett	79.66	136	80	.339	41	.661	213	3.04	713	31	13	10	1061.0	903	358	394	90	364	10	34	37	4,373	24	6.05	3.09	1.96	0.76	16.3	8.3	1.19	.254	3.34	7.66
15	Fernando Valenzuela F. Valenzuela	77.58	166	78	.422	57	.578	176	2.89	1,032	64	23	1	1285.1	1,069	413	485	68	455	9	4	35	5,261	41	7.23	3.19	2.27	0.48	19.6	8.6	1.19	.271	3.40	7.49
16	Dennis Eckersley D. Eckersley	76.61	155	77	.394	50	.606	171	3.13	855	60	13	3	1148.1	1,008	399	431	119	352	32	8	33	4,760	17	6.70	2.76	2.43	0.93	18.0	7.4	1.18	.261	3.38	7.90
17	Frank Tanana F. Tanana	76.59	154	77	.412	54	.588	159	2.72	1,010	79	21	0	1212.0	1,034	366	407	105	322	39	3	22	4,927	30	7.50	2.39	3.14	0.78	20.5	6.5	1.12	.269	3.02	7.68
18	Gary Nolan G. Nolan	75.62	166	76	.382	47	.618	169	2.83	817	33	12	0	1156.2	981	364	407	89	336	12	1	36	4,720	22	6.36	2.61	2.43	0.69	17.3	7.1	1.14	.257	3.17	7.63
19	George Uhle G. Uhle	75.59	125	76	.411	53	.589	190	3.92	313	71	9	9	1051.2	1,176		529	27	312	42	44		4,584	14	2.68	2.67	1.00	0.23	6.8	6.8	1.41	.295	4.53	10.06
20	Mel Harder M. Harder	74.52	136	75	.476	68	.524	236	3.65	390	64	9	13	1198.0	1,299	486	619	45	393	26	61		5,246	13	2.93	2.95	0.99	0.34	7.4	7.5	1.41	.286	4.65	9.76
21	Don Drysdale D. Drysdale	72.55	163	73	.451	60	.549	211	3.28	927	52	15	4	1201.2	1,084	438	486	115	383	67	30	36	5,033	29	6.94	2.87	2.42	0.86	18.4	7.6	1.22	.274	3.64	8.12
22	Catfish Hunter C. Hunter	72.48	190	73	.520	79	.480	212	3.53	882	50	13	1	1319.1	1,170	518	574	151	424	24	4	29	5,471	22	6.02	2.89	2.08	1.03	16.1	7.7	1.21	.255	3.92	7.98
23	Felix Hernandez F. Hernandez	71.57	174	72	.429	54	.571	174	3.18	1,053	14	4	0	1170.2	1,068	414	471	98	360	35	0	14	4,846	60	8.10	2.77	2.93	0.75	21.7	7.4	1.22	.294	3.62	8.21
24	Van Mungo V. Mungo	71.55	141	72	.455	60	.545	182	3.50	623	77	12	7	1133.0	1,071	440	503	45	450	13	30		4,845	24	4.95	3.57	1.38	0.36	12.9	9.3	1.34	.276	4.00	8.51
25	Bret Saberhagen B. Saberhagen	69.56	145	70	.440	55	.560	170	3.46	688	41	9	1	1081.2	1,042	416	450	92	216	15	13	13	4,409	24	5.72	1.80	3.19	0.77	15.6	4.9	1.16	.280	3.74	8.67