Unit book sales will increase only 3.6% between 2003 and 2007, according to projections made by BISG. BISG predicts that total unit sales will reach 2.30 billion in 2007, compared to 2.22 billion in 2003. With the exception of the elhi segment, where unit growth is pegged at 21.1% between 2003 and 2007, only minor gains are predicted for most industry categories. Unit gains in the adult segment are forecasted to be 3%, while a 3.9% increase is projected in the children's segment.