Housing on the islands varies greatly, from the elegant, Mediterranean-style homes of Europeans and middle-class Cape Verdeans to the simple timber and mud-block houses of peasants. At last estimate, approximately 95% of all housing units were one-floor dwellings. External walls were mostly of stone and clay, stone and cement, or all stone. Water supply was delivered by pipes, wells, tanks and cisterns, and other sources. As of 2000, only about 76.7% of the population had access to safe drinking water. At least 54% did not have access to imporved sanitation systems and 50% did not have access to electricity. About 15% of families were homeless.