Categories borrowed from European law fit Haitian mating badly, so Allman works with five terms Haitians use themselves: rinmin, fiyanse, viv avek, plase and marye, separated by whether the partners live together and what economic support passes between them. The 1977 Haiti Fertility Survey, part of the World Fertility Survey programme, supplies the figures, backed by smaller studies in the Artibonite and elsewhere. Legal marriage is uncommon, which he traces to Dessalines' inheritance law of 1805, the expense of weddings, and peasant wariness of officials and documents. Women enter first unions late, spinsterhood after thirty is rare, and plasaj outweighs marriage everywhere, most heavily in the countryside. Around a fifth of rural women said their partner had another woman, against more than forty-five per cent in the cities. Once a woman has begun, she spends about 88 per cent of the following years in some union, which unsettles the usual reading of multiple partners as instability.