Variable

Observation data

Maximum value

Minimum value

Collaboration

450

88

0

Lnpatent1

450

9.803

8.087

Lnpatent2

450

7.301

0

lngd

450

13.950

10.834

in

450

5.53

2.67

gdp

450

26.290

0.068

re

450

2

0

tig

450

1

0