The amount of vacant rental apartments in New York City last year plummeted to the lowest levels they’ve been in decades, with cheaper units particularly hard to come by, a new report found. The city’s net rental vacancy rate dropped to just 1.4%, the worst it’s been since 1968. Between January and June of 2023 a little more than 33,200 units were up for grabs out of a total stock of 2.35 million occupied and available rentals, according to initial findings from the New York City Housing and Vacancy Survey, released Thursday. The report has been compiled approximately every three years since 1…