. 2018 Jul 20;13(7):e0200885. doi: 10.1371/journal.pone.0200885

Table 1. Brazilian twinning rates for the period from 2001 to 2014.

In addition to the individual values for 2001 and 2014, the average value, percentage variation, standard deviation and the parameters estimated in the autoregressive (AR) models are also shown.

Location	Twinning rate (‰)			Variation (%)	Standard deviation	AR (temporal parameter)^a	AR (temporal parameter)^b	Co-variable maternal age ≥ 30^b
Location	2001	2014	Average	Variation (%)	Standard deviation	AR (temporal parameter)^a	AR (temporal parameter)^b	Co-variable maternal age ≥ 30^b
BRAZIL	8.65	10.15	9.41	17.34%	0.50	0.97^*	0.47	0.86^*
NORTH	6.92	7.54	7.31	8.88%	0.24	0.51	-0.35	0.69^*
Roraima	7.68	8.47	8.17	10.22%	0.52	-0.17	-0.53^*	0.54^*
Acre	7.28	9.12	7.54	25.20%	0.76	0.29	0.56	1.38^*
Amazonas	6.42	7.17	7.06	11.73%	0.38	0.11	-0.36	0.72^*
Rondônia	7.51	6.67	6.88	-11.12%	0.98	-0.35	-0.21	0.69
Pará	6.81	7.41	7.19	8.86%	0.25	0.06	-0.21	0.62^*
Amapá	7.32	6.35	7.48	-13.25%	0.71	0.02	0.16	0.59
Tocantins	7.42	8.53	7.76	14.92%	0.57	0.01	-0.57^*	0.66^*
NORTHEAST	8.37	9.07	8.71	8.35%	0.23	0.65^*	0.04	0.55^*
Maranhão	8.56	7.60	8.02	-11.17%	0.34	0.47	0.02	-1.15
Piauí	8.58	8.92	8.45	3.97%	0.58	-0.20	-0.06	0.33
Ceará	8.42	9.29	8.46	10.31%	0.35	-0.46	-0.40	0.44^*
Rio Grande do Norte	8.07	9.00	8.34	11.45%	0.51	0.47	0.34	0.73^*
Paraíba	8.89	9.79	8.99	10.16%	0.47	0.54^*	0.03	0.83^*
Pernambuco	8.37	9.11	8.83	8.84%	0.31	0.44	-0.40	0.71^*
Alagoas	7.34	8.56	8.22	16.74%	0.54	0.05	-0.11	1.39^*
Sergipe	8.42	9.36	9.08	11.19%	0.64	0.09	-0.02	0.81^*
Bahia	8.43	9.69	9.31	14.91%	0.53	0.72^*	-0.11	0.84^*
SOUTHEAST	9.20	11.33	10.34	23.16%	0.73	0.96^*	0.42	0.92^*
Minas Gerais	9.27	10.83	10.13	16.74%	0.65	0.90^*	0.45^*	0.82^*
Espírito Santo	8.47	10.20	9.28	20.47%	0.73	0.87^*	-0.25	0.90^*
Rio de Janeiro	8.88	10.43	9.91	17.45%	0.62	0.84^*	0.41	0.97^*
São Paulo	9.35	11.98	10.69	28.12%	0.84	0.94^*	0.21	0.96^*
SOUTH	9.09	11.02	10.07	21.19%	0.71	0.93^*	0.05	1.17^*
Paraná	9.01	10.58	9.86	17.36%	0.67	0.87^*	-0.51^*	1.21^*
Santa Catarina	8.52	10.72	9.74	25.75%	0.79	0.81^*	0.20	1.18^*
Rio Grande do Sul	9.48	11.70	10.51	23.41%	0.83	0.78^*	-0.18	1.12^*
MIDWEST	8.31	10.17	9.07	22.39%	0.61	0.92^*	-0.27	0.81^*
Mato Grosso do Sul	7.96	9.93	8.73	24.82%	0.58	0.80^*	0.19	1.03^*
Mato Grosso	7.73	10.30	8.70	33.25%	0.83	0.81^*	-0.46^*	0.98^*
Goiás	8.61	9.57	8.91	11.12%	0.57	0.65^*	-0.72^*	0.76^*
Distrito Federal	8.60	11.59	10.12	34.69%	0.89	0.66^*	0.48	0.83^*

^aModel considering only the time period.

^bModel considering time and the co-variable maternal age ≥ 30.

*Stastitically significant at 0.05 level.