Table 1.

Data included by surveys

Data	Survey before the intervention (2012–2013)	Survey after one year of intervention (2014)
	in absolute numbers	in absolute numbers
Sample	840	880
Data collected	754 (90%)	757 (86%)
Data excluded by infant year of birth	7 (born in 2010)	2 (born in 2011)
		16 (born in 2012)
Missing data on date of birth	15	34
Data included	732	705
Data analysed by infant date of birth	Before		After
Infant date of birth	2011–2012	January to June 2013	July to December 2013 and 2014
Data by survey and infant date of birth	732	33	672
Data analysed by period before and after	751		672