Sales of commercial and residential properties were down 49 percent year-to-date through November, according to REBNY. : (Bloomberg)—The pandemic’s slowdown in real estate deals has cost New York City $1.2 billion in lost revenue so far this year. Sales of commercial and residential properties -- everything from office buildings to hotels and condo units -- are down 49% this year through November, according to a report Thursday by the Real Estate Board of New York. That’s led to a 42% decline in city tax revenue, compared with the same 11-month period in 2019, the trade group said.