My partner and I have one location with back to back digital billboards. They are smaller, at 7'hX12' w, are almost two years old, 16mm pitch, are located along a business route with a daily traffic count of about 20,000 vehicles. We have had a difficult time attracting advertisers and are looking to sell the signs with the ground lease. I remember seeing a formula based on income from the signs that determined their value. I haven't been able to find that post, can anyone help me? Thanks.