Model of Automobile Parts Sale Prediction Based on Nonlinear Periodic Gray GM(1,1) and Empirical Research

Table 2

Automotive seat sales of F-Company in 2012–2018 (unit: ten thousand).

Year	Month sales
	1	2	3	4	5	6	7	8	9	10	11	12
2012	15.21	15.03	18.23	16.54	20.36	19.63	13.64	19.05	24.36	23.15	20.48	22.36
2013	16.14	15.96	18.63	16.5	20.15	19.56	13.42	19.52	24.65	23.54	21.35	21.41
2014	16.89	16.52	19.54	16.34	20.01	20.82	14.76	18.06	25.13	23.68	21.68	21.59
2015	17.05	16.98	19.15	16.8	20.08	20.93	14.07	18.16	25.52	23.98	21.51	21.65
2016	17.04	17.06	17.84	16.35	20.6	20.41	15.46	19.42	26.6	27.37	24.28	27.52
2017	17.11	17.62	19.56	16.52	20.89	21.06	16.58	20.25	26.72	27.69	24.39	27.88
2018	18.16	18.10	20.45	18.12	22.21	22.14	16.32	20.89	27.85	27.41	24.51	25.91