Statistical summary

Unitary and Majoritarian System: 13/170 = 7.6%
Unitary and Proportional System: 7/170 = 4%
Unitary and Mixed System: 4/170 = 2%
Unitary and Majoritarian System and Nomination: 14/170 = 2.9%
Unitary and Proportional System and Nomination: 5/170 = 3%
Unitary and Majoritarian, Proportional, and Nomination System: 2/170 = 1%
Unitary and Nomination System: 18/170 = 11%
Unitary and With an Upper House: 63/170 = 36%
Unitary and Without an Upper House: 107/170 = 64%