Just over 13,000 students across New York state earned a high-school equivalency diploma in 2014 after the debut of a new, tougher set of tests — 20,000 fewer than the number who earned a GED at a 2008 peak.

The drop in the number of students taking and passing the tests was expected, but the figures released Monday by the State Education Department are the first showing the extent of the decline.

The changes follow the state’s 2013 decision to replace the GED, which was about to grow much more expensive as it became a computer-based test that incorporated the Common Core standards. New York’s chosen replacement, known as TASC, requires students to pass tests in the same five subjects as the GED. But the TASC tests require more advanced math skills and specific content knowledge in science, offering an additional set of challenges for students and prompting many to spend more time preparing.

The state’s report notes that the percentage of students who passed the test in 2014 was identical to the pass rate in 2012, around 53 percent. (The state is treating 2013 as an anomaly, since a higher than average number of students tried to take the GED that year before it was phased out.)

All told, 22,598 New York students took all five TASC tests, 11,281 earned their diplomas by passing all of them, and another 1,876 earned their diplomas by combining passing scores on GED tests and TASC tests, according to the state’s preliminary figures. New York City-specific pass rates were not included, though the percentage of the state’s test-takers from the city remained steady at 57 percent.