Mark Cotteleer owns a company that manufactures sailboats. What was Mark's actual demand for the sailboats during each season in 2006 through 2009 as follows:
Season 2006 2007 2008 2009
Winter 1,400 1,200 1,000 900
Spring 1,500 1,400 1,600 1,500
Summer 1,000 2,100 2,000 1,900
Fall 600 750 650 500
Mark has forecasted that annual demand for his sailboats in 2011 will equal 5,600 sailboats. based on this data and the multiplicative seasonal model, what will the demand level be for Mark's sailboats in the spring of 2011?