Table 1.

The number of sampled farms and pigs in different years and regions in Henan province, China.

Regions	The number of sampled farms					The number of sampled pigs
	2015	2016	2017	2018	Total	2015	2016	2017	2018	Total
An yang	0	1	1	0	2	0	2	4	0	6
He Bi	1	4	3	1	9	3	8	12	3	26
Ji Yuan	0	0	2	0	2	0	0	6	0	6
Kai Feng	4	2	5	1	12	15	6	14	2	37
Luo Yang	1	5	1	0	7	1	17	6	0	24
Luo He	0	0	1	0	1	0	0	3	0	3
Nan Yang	3	3	4	1	11	4	20	17	2	43
Ping Dingshan	3	1	3	1	8	7	6	18	6	37
Pu Yang	2	2	6	1	11	10	16	51	2	79
San Menxia	0	1	3	0	4	0	1	9	0	10
Zheng Zhou	1	0	4	1	6	2	0	10	3	15
Xin Xiang	1	3	1	0	5	2	7	5	0	14
Xin yang	0	0	3	2	5	0	0	3	3	6
Zhou Kou	2	3	4	2	11	5	8	27	31	71
Zhu Madian	1	0	5	0	6	7	0	21	0	28
Shang Qiu	1	1	4	1	7	3	1	17	1	22
Xu Chang	0	0	1	1	2	0	0	1	2	3
Total	20	26	51	12	109	59	92	224	55	430