Table 4 The results of the fixed effects model regression

year dummies

β

−0.004***

−0.004***

−0.004***

− 0.004***

−0.001

− 0.004***

− 0.005***

− 0.004***

−0.004***

− 0.003***

SD

< 0.001

< 0.001

< 0.001

< 0.001

< 0.001

< 0.001

< 0.001

< 0.001

< 0.001

< 0.001

ln (doc)

β

−0.616***

−0.765***

− 0.808***

−0.894***

−1.003***

−1.045***

−1.130***

−1.011***

− 0.986***

−0.971***

SD

0.103

0.126

0.138

0.148

0.162

0.167

0.164

0.177

0.182

0.179

ln (gdp)

β

−0.152**

−0.111

−0.053

− 0.038

−0.085

− 0.043

−0.073

0.027

0.06

0.048

SD

0.052

0.067

0.074

0.080

0.089

0.093

0.090

0.101

0.106

0.103

ln (gdp)*ln (doc)

β

0.044**

0.044*

0.04*

0.044*

0.054*

0.051*

0.067**

0.043

0.039

0.042

SD

0.014

0.017

0.019

0.020

0.022

0.023

0.023

0.024

0.025

0.026

lngdp²*ln (doc)

β

−0.001

−0.001

−0.001

−0.001

−0.001

−0.001

−0.002**

− 0.001

−0.001

− 0.001

SD

< 0.001

0.001

0.001

0.001

0.001

0.001

0.001

0.001

0.001

0.001

ln (pop)

β

−0.003

0.003

0.009

0.013*

−0.011

0.022**

0.027***

0.035***

0.039***

0.036***

SD

0.004

0.005

0.006

0.006

0.007

0.007

0.007

0.008

0.008

0.008

ln (gov)

β

0.071***

0.095***

0.118***

0.149***

0.042***

0.192***

0.219***

0.222***

0.232***

0.225***

SD

0.008

0.011

0.012

0.013

0.009

0.015

0.015

0.017

0.017

0.016

AIC

− 3637.371

− 1975.381

− 1265.98

− 835.235

−337.375

− 423.285

−318.55

− 426.805

− 448.377

− 546.82

BIC

− 3617.57

− 1955.745

− 1246.518

− 815.958

−318.295

−404.415

−299.907

− 408.406

−430.243

−528.977

−2 log like lihood

− 3643.375

−1981.385

− 1271.985

− 841.24

− 343.381

− 429.291

− 324.556

−432.812

−454.385

−552.829

Dependent Variable: ln (bed)

year dummies

β

−0.003***

−0.004***

−0.005***

−0.005***

−0.001

−0.003***

− 0.002***

−0.002***

− 0.001***

−0.001**

SD

< 0.001

< 0.001

< 0.001

< 0.001

0.001

< 0.001

< 0.001

< 0.001

< 0.001

< 0.001

ln (bed)

β

−0.057

−0.093

0.184

0.051

−0.049

−0.431**

− 0.76***

−1.078***

−1.269***

−1.293***

SD

0.065

0.084

0.104

0.120

0.136

0.143

0.151

0.155

0.158

0.162

ln (gdp)

β

0.134***

0.249***

0.560***

0.590***

0.543***

0.354***

0.119

−0.118

−0.323**

−0.440***

SD

0.037

0.048

0.060

0.070

0.080

0.086

0.093

0.097

0.101

0.105

ln (gdp)*ln (bed)

β

−0.003

−0.005

−0.043**

− 0.028

−0.016

0.026

0.064**

0.102***

0.122***

0.118***

SD

0.009

0.011

0.014

0.016

0.018

0.019

0.020

0.021

0.022

0.022

lngdp²*ln (bed)

β

−0.000*

−0.001**

−0.001*

−0.002***

− 0.002***

−0.003***

− 0.003***

−0.004***

− 0.004***

−0.003***

SD

< 0.001

< 0.001

< 0.001

< 0.001

0.001

0.001

0.001

0.001

0.001

0.001

ln (pop)

β

0.008***

0.019***

0.033***

0.041***

0.013**

0.042***

0.040***

0.039***

0.040***

0.042***

SD

0.002

0.003

0.004

0.005

0.005

0.006

0.006

0.006

0.006

0.006

ln (gov)

β

0.060***

0.104***

0.148***

0.170***

0.028***

0.149***

0.113***

0.079***

0.051***

0.028*

SD

0.005

0.006

0.008

0.009

0.007

0.012

0.012

0.013

0.014

0.014

AIC

− 9835.489

− 6943.795

− 5241.642

− 4034.877

− 2839.135

− 2492.198

− 2151.791

−2030.466

− 1934.433

− 1898.389

BIC

− 9815.688

− 6924.159

− 5222.18

− 4015.599

− 2820.055

− 2473.328

− 2133.148

−2012.067

− 1916.299

− 1880.546

−2 log likelihood

− 9841.493

− 6949.800

− 5247.647

− 4040.882

− 2845.141

− 2498.204

− 2157.797

− 2036.473

− 1940.441

− 1904.397