变量	回归1	回归2	回归3
Po_Med	0.000889^***	0.000894^***	0.000495^***
Po_Med	(0.000163)	(0.000164)	(0.000176)
Lev		-0.000148	-0.000109
Lev		(0.000318)	(0.000317)
ROE		0.000399	0.000442
ROE		(0.000283)	(0.000282)
Growth		−0.0000151	−0.0000141
Growth		(0.0000268)	(0.0000268)
year			0.001^***
year			(6.12)
_cons	0.00988^***	0.00993^***	0.00795^***
_cons	(0.000718)	(0.000722)	(0.000789)
N	6952	6952	6952
R²	0.004	0.005	0.010