New York City’s construction industry is likely to hit bottom this year after three straight years of dismal declines, according a forecast released yesterday by the New York Building Congress. Construction spending will only reach $23.7 billion this year, down 12 percent from 2009, and down 23 percent from 2008, when it peaked at $31 billion. Construction should pick up, predicted the report, but much of the industry’s growth is dependent on whether the MTA can fund its 2012 capital plan, which includes projects like the Second Avenue Subway and East Side Access.