Table 1. Characteristics of survey participants, the Netherlands, baseline survey 2016–17^a, April 2020 and June 2020.

Characteristics	Baseline surveya		April 2020 survey		June 2020 survey
	n	%	n	%	n	%
Total	5,066	100	2,069	100	6,300	10
Age group (years)
0–4	377	7.4	39	1.9	118	1.9
5–9	321	6.3	110	5.3	256	4.1
10–19	597	11.8	194	9.4	575	9.1
20–29	781	15.4	275	13.3	662	10.5
30–39	689	13.6	331	16.0	736	11.7
40–49	613	12.1	312	15.1	859	13.6
50–59	563	11.1	318	15.4	1,028	16.3
60–69	647	12.8	279	13.5	1,163	18.5
70–79	397	7.8	179	8.7	770	12.2
≥ 80	81	1.6	32	1.5	133	2.1
Sex
Female	2,803	55.3	1,156	55.9	3,490	55.4
Male	2,263	44.7	913	44.1	2,810	44.6
Household sizeb
1	882	17.4	168	8.1	700	11.1
2	1,844	36.4	727	35.1	2,499	39.7
3	667	13.2	359	17.4	902	14.3
4	1,068	21.1	562	27.2	1,496	23.7
5	451	8.9	197	9.5	543	8.6
≥ 6	154	3.0	56	2.7	160	2.5
Contact day
Monday	918	18.1	521	25.2	1,113	17.7
Tuesday	831	16.4	546	26.4	1,047	16.6
Wednesday	517	10.2	368	17.8	1,004	15.9
Thursday	264	5.2	205	9.9	672	10.7
Friday	428	8.4	102	4.9	367	5.8
Saturday	683	13.5	79	3.8	746	11.8
Sunday	980	19.3	246	11.9	1,348	21.4
Missing	445	8.8	2	0.1	3	0.0

^a The baseline survey took place from February 2016 to October 2017.

^b Households in the Netherlands consist of one (38%), two (33%), three (12%), four (12%) and more than 5 (5%) persons [17], leading to the following expected household size distribution per participant: one (17%), two (31%), three (17%), four (23%) or more than five (12%) persons.