Table 2.

Percentages of missing data for each identification item, among false positives, for each year.

Years	Maiden name (%)	Mother's first name (%)	Mother's date of birth (%)	Infant's first name (%)	Infant's date of birth (%)	Zip code (%)
1998	43.75	18.75	18.75	46.88	40.63	18.75
1999	33.33	33.33	20.00	56.67	53.33	20.00
2000	3.71	1.68	1.89	22.46	16.72	1.33
2001	89.87	90.08	0.21	97.89	97.68	0.21
2002	78.30	79.05	29.68	97.01	96.51	0.50
2003	84.94	84.39	0.37	98.14	98.14	0.37
2004	69.33	56.30	0.14	86.41	95.38	0.00
2005	82.49	58.82	8.70	74.76	79.11	8.82
2006	75.21	71.05	0.07	97.02	97.85	0.14