Table 2. Worldwide frequencies of ptxP1 and ptxP3 during 1935–1990 and 1991–2004*.

Region†	1935–1990					1991–2004
	ptxP1	ptxP3	Other‡	N		ptxP1	ptxP3	Other‡	N
The Netherlands	89	3	8	265		47	53	0	614
Africa	100	0	0	11		100	0	0	7
Asia	100	0	0	12		83	13	3	30
Europe§	73	0	27	22		46	53	0	577
North America	50	13	38	8		20	80	0	10
South America	–	–	–	0		10	80	10	10
Total	88	3	9	318		47	52	1	1,248

*ptxP, pertussis toxin promoter. Allele frequencies are given in percentages.
†The following countries represented the continents: Africa: Senegal; Asia: Japan and Australia; Europe: Denmark, Finland, France, Germany, Italy, Sweden; North America: USA; South America: Argentina.
‡Nine ptxP alleles were found in low frequencies: ptxP2, ptxP4, ptxP5, ptxP6, ptxP7, ptxP8, ptxP9, ptxP10, and ptxP11.
§Dutch strains were excluded.