It received papal visits from three successive supreme pontiffs: Pope John Paul II (January 1998), Pope Benedict XVI (March 2012) and Pope Francis (September 2015). The Jewish community in Havana has reduced after the Revolution from once having embraced more than 15,000 Jews, many of whom had fled Nazi persecution and subsequently left Cuba to Miami or moved to Israel after Castro took to power in 1959. The city once had five synagogues, but only three remain (one Orthodox, and two Conservative: one Conservative Ashkenazi and one Conservative Sephardic), Beth Shalom Grand Synagogue is one of them and another that is a hybrid of all 3 put together. In February 2007 the New York Times estimated that there were about 1,500 known Jews living in Havana. The years after the Soviet Union collapsed in 1991, the city, and Cuba in general have suffered decades of economic deterioration, including Special Period of 1990s. The national government does not have an official definition of poverty. The government researchers argue that "poverty" in most commonly accepted meanings does not really exist in Cuba, but rather that there is a sector of the population that can be described as "at risk" or "vulnerable" using internationally accepted measures. The generic term "slum" is seldom used in Cuba, substandard housing is described: housing type, housing conditions, building materials, and settlement type. The National Housing Institute considers units in "solares" (a large inner-city mansion or older hotel or boarding house subdivided into rooms, sometimes with over 60 families) and shanty towns to be the "precarious housing stock" and tracks their number. Most slum units are concentrated in the inner-city municipalities of Old Havana and Centro Habana, as well as such neighbourhoods as "Atarés" in Regla. People living in slums have access to the same education, health care, job opportunities and social security as those who live in formerly privileged neighbourhoods. Shanty towns are scattered throughout the city except for in a few central areas. Over 9% of Havana's population live in "cuartería" ("solares, ciudadela"), 3.3% in shanty towns, and 0.3% in refugee shelters. This does not include an estimate of the number of people living in housing in "fair" or "poor" condition because in many cases these units do not necessarily constitute slum housing but rather are basically sound dwellings needing repairs. According to "Instituto Nacional de Vivienda" (National Housing Institute) official figures, in 2001, 64% of Havana's 586,768 units were considered in "good" condition, up from 50% in 1990.