The percentage of residential properties with city liens sold as tax certificates at the annual tax lien certificate sale held in May. Tax sales are used to collect delinquent real property taxes and other unpaid charges to the city, which are liens against the real property. The tax certificate sale is a public online auction of City lien interests on properties that occurs annually in May. Source: BidBaltimore Years Available: 2015, 2016, 2017, 2018, 2019