VT I
Niger
Answer
40.11%
Source
There is only one secondary source reporting the participation in legislative elections in Niger in 1999:
http://democratie.francophonie.org/IMG/pdf/RAPPORT_DE_LA_MISSION_D_OBSERVATION_DES_ELECTIONS_PRESIDENTIELLES_ET_LEGISLATIVES_DES_17_OCTOBRE_ET_24_NOVEMBRE_1999_.pdf
