New York City’s graduation rate hit a record 74 percent in 2017, according to preliminary figures published on the education department website this week, a slight increase over the previous year.

The numbers continue an upward trend for the city — where the overall graduation rate has grown by nearly 28 points since 2005 — and are in line with previous increases under Mayor Bill de Blasio. This year’s unofficial rate is 1 percentage point higher than the 2016 preliminary rate, and 1.4 points higher than last year’s official rate.

City officials cautioned that the state has not yet verified the figures, which are still subject to change. State officials said they will not release official graduation rates until 2018. Last year, the city’s preliminary graduation rate was 73 percent, while the official rate was 72.6.

Graduation rates are widely considered to be an indicator of the school system’s overall health. Their upward trajectory — even if less steep than previous years — is a good sign for the de Blasio administration.

“This year’s number will be a record high,” said Aaron Pallas, a professor at Teachers College. “That’s something the administration can crow about and take pride in.”

The citywide graduation rate was included on the latest “School Quality Reports,” guides the city education department publishes online each year to help families evaluate schools and compare their performance to the city average. The 2017 reports were posted this week.

“The graduation rate in the School Quality Reports is preliminary and, as always, the official citywide graduation rate will be released by the state later this school year,” said department spokeswoman Toya Holness.

Among struggling schools in de Blasio’s high-profile Renewal turnaround program, the news was mixed. More than half of the high schools in that $568 million program — 19 out of 28 — missed the graduation goals the city set for them, the New York Times reported Thursday. Six of the schools saw declines.

A wide gulf remains between the share of students who graduate high school and those who are ready for college-level work. Just 46 percent of New York City students last year met the academic benchmarks necessary to avoid remedial classes at CUNY schools, according to numbers released this week.

“Historically, there are fears that it’s been possible for kids to graduate without necessarily demonstrating the skills and competencies they need to succeed in college without remediation,” Pallas said.

Mayor de Blasio set a goal of graduating 80 percent of students by 2026, a metric the city will achieve if the graduation rate continues to inch up by even 1 percentage point each year. He has launched several initiatives to advance that goal, including a plan to better prepare students for algebra — which is often a stumbling block for students.

Meanwhile, the state has made it easier for some students to earn a diploma.

Students with disabilities can now graduate by passing only two Regents exams, while most students must pass five. At the same time, more students are now eligible to appeal a failed Regents exam and students can substitute a skills certificate for a final Regents exam.

Monica Disare contributed reporting.