GARDEN CITY, N.Y. — Long Island Rail Road officials are blaming the weak economy for the largest annual drop in ridership in four decades on the nation’s largest commuter railway.

Total LIRR ridership in 2009 was about 83 million, down from about 87 million in 2008. The 2008 figure was the highest since 1949.

LIRR officials note that 84,000 jobs were lost in New York City last year, which could account for some of the drop-off. Thousands of Long Islanders commute into New York for work.

The drop in ridership caused a $27 million loss in fare revenue compared with 2008.