The St. Louis Blues had their highest power-play percentage in a season in 2021-22, at 27.0 percent.

when did the blues have their best power play percentage in a season

TEAM	PP%	SEASON	GP	W	L	T	OTL	PTS	PTS%	G	GA	PK%	S/GP	SA/GP
St. Louis Blues	27.0	2021-22	82	49	22		11	109	.665	309	239	84.1	30.39	31.60
St. Louis Blues	24.6	1986-87	80	32	33	15		79	.494	281	293	81.4	29.34	29.55
St. Louis Blues	24.3	2019-20	71	42	19		10	94	.662	223	190	79.3	30.69	29.58
St. Louis Blues	24.2	1980-81	80	45	18	17		107	.669	352	281	82.0	30.39	31.75
St. Louis Blues	23.2	2020-21	56	27	20		9	63	.563	167	167	77.8	28.96	29.82
St. Louis Blues	22.5	1981-82	80	32	40	8		72	.450	315	349	76.2	30.79	32.23
St. Louis Blues	22.5	1989-90	80	37	34	9		83	.519	295	279	80.9	29.16	29.50
St. Louis Blues	22.4	1983-84	80	32	41	7		71	.444	293	316	74.8	30.33	30.00
St. Louis Blues	22.3	2014-15	82	51	24		7	109	.665	239	197	83.7	30.91	27.23
St. Louis Blues	21.9	1984-85	80	37	31	12		86	.538	299	288	76.1	31.08	29.81
St. Louis Blues	21.9	1992-93	84	37	36	11		85	.506	282	278	83.7	29.04	33.81
St. Louis Blues	21.5	1985-86	80	37	34	9		83	.519	302	291	77.2	31.44	32.25
St. Louis Blues	21.5	2015-16	82	49	24		9	107	.652	219	197	85.1	30.17	29.74
St. Louis Blues	21.3	1982-83	80	25	40	15		65	.406	285	316	81.3	31.29	31.18
St. Louis Blues	21.3	2016-17	82	46	29		7	99	.604	233	216	84.8	28.41	28.38
St. Louis Blues	21.1	2018-19	82	45	28		9	99	.604	244	220	81.5	31.76	28.60
St. Louis Blues	20.5	2008-09	82	41	31		10	92	.561	227	227	83.8	27.70	28.55
St. Louis Blues	20.5	1993-94	84	40	33	11		91	.542	270	283	81.2	30.60	35.07
St. Louis Blues	20.5	2002-03	82	41	24	11	6	99	.604	253	222	81.7	28.06	24.96
St. Louis Blues	20.3	1998-99	82	37	32	13		87	.530	237	209	87.9	30.11	22.78
St. Louis Blues	20.1	1990-91	80	47	22	11		105	.656	310	250	83.8	31.88	29.31
St. Louis Blues	20.0	1988-89	80	33	35	12		78	.488	275	285	76.7	29.09	28.09
St. Louis Blues	19.9	1987-88	80	34	38	8		76	.475	278	294	79.4	28.56	30.31
St. Louis Blues	19.8	2013-14	82	52	23		7	111	.677	239	188	85.7	29.29	26.38
St. Louis Blues	19.5	2012-13	48	29	17		2	60	.625	124	114	84.7	27.83	24.19