A report released this week predicts the building boom in New York City will reach its peak this year. The New York Building Congress report predicts the number of construction jobs will decline by 30,000 by 2010. Meanwhile, construction spending will fall from $33.8 billion this year to $26.2 billion in 2010. The downturn in the economy has cast doubt on some projects, according to the report. "This is such an uncertain situation that it is almost impossible to say with confidence what the forecast for the construction market will be over the next several years," said Richard Anderson, president of the building congress.