Table 1. Age distribution of inhabitants of 3 northern provinces in the study, the Netherlands.

Province	Age range, y					Total, all ages
	0–15	16–24	25–44	45–64	>65
Groningen	99,065	72,714	164,371	151,590	86,818	574,558
Friesland	125,174	70,397	174,768	172,600	99,665	642,604
Drenthe	92,241	45,885	127,674	136,915	81,212	483,927
Total	316,480	188,996	466,813	461,105	267,695	1,701,089