Table 1. Characteristics of study population.

Variable	Year
	2005	2006	2007	2008	2009	2010	2011	2012	2013	2014
Number	1,140	1,642	2,050	6,207	14,101	60,846	83,586	76,906	84,102	93,665
Age	31.0±20.4	34.1±18.4	35.7±17.7	37.6±17.4	38.4±14.9	37.5±12.8	37.5±12.6	37.7±12.9	38.1±12.9	37.8±12.4
Male-to-female ratio	1:0.76	1:0.82	1:0.74	1:1.00	1:0.93	1:1.12	1:1.35	1:1.64	1:1.49	1:1.49
Age group
0~9	231	158	151	401	294	787	613	1,130	1,108	854
10~19	141	224	245	445	1,049	3,313	3,601	3,068	2,707	3,007
20~29	171	314	347	1,217	2,500	11,996	16,299	14,008	15,011	17,529
30~39	225	341	470	1,540	4,191	20,528	30,902	29,321	32,231	37,263
40~49	156	265	393	1,203	2,991	13,162	17,495	14,918	17,191	18,252
50~59	104	180	255	775	1,819	7,854	10,041	10,118	10,757	11,607
60+	112	16	189	716	1,257	3,206	4,635	4,343	5,097	5,153