Table 1.

Submodels of different historical periods and corresponding assumptions.

Submodel	Assumptions	Historical Period
I	${\delta }_i=0$ and $T_i^g=0,R_i^g=0$, $i=1,2,3$, $g=w,mw,mm,b$	1992–2002
II	${\delta }_i=0$ and $T_i^g=0$, $i=1,2$, $g=w,mw,mm,b$	2003–2011
III	${\delta }_1=0$ and $T_1^g=0$, $g=w,mw,mm,b$	2012–2015
IV	The full model	2016–now