Table 1. Percentage (%) of performance improvement between the competitive seasons.

Event	15/16 – 16/17	16/17 – 17/18	17/18 – 18/19	18/19 – 19/20	Overall variation (%) 15/16 – 19/20
Freestyle
50-m	0.98 ± 1.61	0.16 ± 1.59	0.90 ± 1.66	-1.94 ± 1.82	0.09 ± 2.28
100-m	1.02 ± 1.58	0.16 ± 1.22	0.79 ± 1.23	-2.06 ± 1.95	0.02 ± 2.58
200-m	1.33 ± 2.20	0.73 ± 2.99	0.57 ± 2.27	-1.57 ± 2.09	1.10 ± 3.50
400-m	0.91 ± 2.19	1.20 ± 2.58	1.37 ± 4.27	-2.06 ± 3.42	1.55 ± 4.91
800-m	1.28 ± 2.43	1.46 ± 2.15	0.85 ± 1.38	-1.02 ± 1.69	2.67 ± 4.20
1500-m	1.21 ± 2.27	0.77 ± 1.56	0.66 ± 1.28	-1.11 ± 1.64	1.66 ± 3.44
Backstroke
100-m	0.93 ± 2.43	1.18 ± 1.87	0.79 ± 1.39	-0.90 ± 1.76	2.00 ± 3.74
200-m	1.25 ± 2.24	0.86 ± 1.63	0.56 ± 1.25	-1.62 ± 2.06	1.39 ± 4.39
Butterfly
100-m	2.03 ± 3.65	0.44 ± 1.84	0.98 ± 1.83	-1.36 ± 1.90	2.05 ± 4.88
200-m	1.40 ± 2.09	0.75 ± 1.93	0.53 ± 1.26	-2.03 ± 2.21	0.73 ± 3.99
Breaststroke
100-m	0.82 ± 1.93	0.85 ± 1.80	0.40 ± 1.42	-1.13 ± 1.57	0.89 ± 2.60
200-m	0.68 ± 1.74	0.55 ± 1.38	0.61 ± 1.09	-1.99 ± 1.94	-0.09 ± 2.97