How do you forecast General and administrative expenses for an income statmenent for example: How would I find SG&A for 2006?

Income Statement	2002	2003	2004	2005
Revenue	128,979	143,560	161,863	185,815
Cost of Goods Sold	100,857	111,203	125,756	144,594
Gross Margin	28,122	32,357	36,107	41,221
G&A Charges	12,482	13,685	18,131	17,327
EBIT	15,639	18,672	17,976	23,894
Interest	4,537	6,150	5,964	5,695
Earnings After Interest	11,102	12,522	12,012	18,199
Tax	3,882	4,288	4,312	6,210
Net Income	7,220	8,234	7,700	11,989

2006:

Expected Forecast
Yards Sold (thousands)	2,200
Average Price Per Yard	$95.36
Average Cost Per Yard	$75.59
Capital Expenditure	16,000
Depriciation	7,500
Income Statement
Revenue	209,792
Cost of Goods Sold	166,298
Gross Margin	43,494
General & Administrative
EBIT
Interest
Tax
Net Income