A broad measure of joblessness that includes those who are forced into part-time jobs or have become so discouraged that they’ve stopped looking for work fell in Hawaii last year to its lowest level in four years, according to a report released Tuesday.

The rate, which represents what some economists refer to as "hidden unemployment," dropped to 12.8 percent in 2012 from 15.1 percent in 2011, the U.S. Bureau of Labor Statistics reported. The 2012 rate was the lowest since 2008 when it was 8.8 percent.

The number of unemployed Hawaii residents totaled 38,600 in 2012. There also were 34,000 workers who were employed part time involuntarily because they could not find full-time work due to "slack work or business conditions," the bureau reported.

In addition, there were 10,600 individuals classified as "marginally attached" to the labor force, who had looked for work at some point during the previous 12 months but not in the four weeks before the survey was taken. Within the marginally attached group, 2,900 were classified as "discouraged workers" because they indicated in their telephone interview they were not looking for work because they believed no jobs were available for them.

The bureau uses a monthly telephone survey of households to gather data from which it calculates the various unemployment rates.

The bureau calculates six levels of unemployment. Tuesday’s report, which is reported for individual states on a quarterly basis, included all six.

The "U-6" rate, which is the broadest measure of unemployment, encompasses the official "U-3" rate, which is reported for states on a monthly basis.

Hawaii’s U-6 rate in 2012 was the 17th lowest among all 50 states, the bureau reported. The U-6 rates ranged from a low of 6.1 percent in North Dakota to a high of 20.3 in Nevada. The national average was 14.7 percent.

Hawaii’s U-3 jobless rate averaged 5.8 percent in 2012, the lowest since 2008 when it averaged 4.1 percent for the year. The national U-3 unemployment rate averaged 8.1 percent in 2012.