Table 2.

Proportion of deaths reported as unknown or unclassified

Publication	Proportion unknown/unclassified (%)
Langhoff‐Roos et al. (1996)	<1
Whitfield et al. (1986), Cole et al. (1986), Alberman (1994), Winbo et al. (1997)	<5
Hovatta et al. (1983), de Galan‐Roosen et al. (2002)	5–10
Gardosi et al. (2005), Korteweg et al. (2006), Varli et al. (2008)	11–20
Chang et al. (1979), Fretts et al. (1992)	21–30
Baird et al. (1954)	31–40
Knutzen et al. (1975), Winbo et al. (1998), Keeling et al. (1989)	41–50