Statistical summary

Unitary and Majoritarian System: 54/170 = 32%
Unitary and Proportional System: 65/170 = 40%
Unitary and Mixed System: 37/170 = 22%
Unitary and Majoritarian and Nomination System: 9/170 = 5%
Unitary and Proportional and Nomination System: 1/170 = 1%
Unitary and Nomination System: 1/170 = 1%
Unitary and No Lower House: 3/170 = 5%