Homebuyers in Brooklyn are snapping up condominiums faster than developers are filing for new ones. In 2016, the number of new residential condo units planned for the borough fell to 1,848, a 34 percent decrease relative to 2015, while the number of condo sales increased each quarter. In January, keeping with the trend, there were 13 condo offerings with a total of 171 residential units filed with the New York State Attorney General’s Office.