Pourdir and zero-marking are distributed nearly equally whereas ki is much more rare and tends to occur more often in written style.
Source: Bollée and Rosalie 1994: 192
Source: Bollée and Rosalie 1994: 204
Source: Bollée and Rosalie 1994: 192
Source: Bollée and Rosalie 1994: 258f.
Source: Bollée and Rosalie 1994: 192