California/Brisbane positive	California/Denver positive	California/1918 positive
naïve	3 of 7 (42%)	3 of 7 (42%)	0 of 7 (0%)
1920	9 of 24 (37.5%)	8 of 24 (33.3%)	19/24 (79.1%)
1930	0 of 5 (0%)	0 of 5 (0%)	1 of 5 (20%)
1940	4 of 13 (30.8%)	10 of 13 (76.9%)	7 of 13 (53.8%)
1950	3 of 20 (1.5%)	13 of 20 (65%)	14 of 20 (70%)
1960	7 of 17 (41.1%)	11 of 17 (64.7%)	13 of 17 (76.5%)
1970	5 of 11 (45.5%)	3 of 11 (27.3%)	10 of 11 (90.9%)
1980	11 of 18 (61.1%)	11 of 18 (61.1%)	12 of 18 (66.7%)
1990	29 of 42 (69%)	20 of 42 (47.6%)	17 of 42 (40.5%)
2000	14 of 24 (58.3%)	8 of 24 (33.3%)	5 of 24 (20.8%)
	CA/Bris/Den positive	CA/Bris/1918 positive	CA/Den/1918 positive
naïve	2 (28.6%)	0	0
1920	0	1 (4.2%)	1 (4.2%)
1930	0	0	0
1940	3 (23.1%)	0	3 (23.1%)
1950	0	0	4 (20%)
1960	0	0	2 (11.8%)
1970	0	3 (27.3%)	0
1980	3 (16.7%)	1 (5.6%)	0
1990	8 (19%)	2 (4.8%)	1 (2.4%)
2000	4 (16.7%)	0	0
	CA/Bris/Den/1918 positive
naïve	0
1920	5 (20.9%)
1930	0
1940	1 (7.7%)
1950	2 (10%)
1960	6 (35.3%)
1970	2 (18.2%)
1980	7 (38.9%)
1990	8 (19%)
2000	3 (12.5%)