TRENTON-Nineteen out of 20 public school teachers in New Jersey are considered ``highly qualified'' to do their jobs, according to a new state Education Department study. That puts the state in good standing under the federal No Child Left Behind education law, which requires that teachers prove they know the subjects they teach. The federal government requires that by the end of the next school year every teacher meet the standard. The ``highly qualified'' designation means teachers can demonstrate expertise in the subjects they teach through their college major, course credits, passing tests or other measures. It does not, however, address how well the teachers teach. In New Jersey last year, 96 percent of elementary school teachers, 94 percent in middle schools, 95 percent in high schools and 95 percent of teachers overall met the criteria. New Jersey is doing slightly better than the nation as a whole, where 93 percent of teachers met the standards. Getting to 100 percent in a year is not assured, though. ``We want to work with all of our schools to see that they have as many highly qualified people as possible,'' state Education Commissioner William J. Librera said Tuesday. Statewide, about 75 school districts had fewer than 90 percent of their teachers meet the standards.