Table 3 Slope of linear regressions of annual cumulative proportions of WR for the major 6 countries.

T & F Men	1920-1939	1950-1969	1970-1989	1990-2008
USA	0.005	0.0071	0.0027	0.0013
RUS		0.0033	0.0022	0.0003
ALL	0.0011	0.0003	0.0005	0
GDR			0.0015*	-
CHN			0.0002	0.0003
GBR	0.0002	0.0005*	0.0013	0.0002
T & Women
USA	0.0007	0.0005	0.0022	0.0006
RUS	0.0002	0.0047	0.0041	0.0018
ALL	0.0031	0.0005	0.0005	0
GDR		0.0004	0.0071	-
CHN		0.0002	0.0002	0.0009
GBR	0.0012	0.0004	0.0005*	0.0005*
Swimming Men
USA	0.0037	0.0075	0.0063	0.0031
RUS		0.0009	0.0012	0.0005
ALL	0.0007	0.0001	0.0007	0.0003*
GDR		0.0007	0.0042	-
CHN			0	0.0005
AUS	0.0002	0.0024	0.0007*	0.0022
Swimming Women
USA	0.0043*	0.008	0.0041	0.0015
RUS		0.0006	0.0006	0
ALL	0.0007	0	0	0.0006*
GDR		0.0008	0.0091	-
CHN			0.0001	0.0012
AUS	0.0003*	0.0022	0.0010*	0.0017*

P <0.001 for all the results except those indicated* T & F = Track & Field