The consumption of lead is growing at 4% per year. It has a number of uses, principally as electrodes in storage batteries, as roofing and pipe-work on buildings, and as pigment for paints. The first...

The consumption of lead is growing at 4% per year. It has a number of uses, principally as electrodes in storage batteries, as roofing and pipe-work on buildings, and as pigment for paints. The first two of these allow recycling, the third does not. Batteries consume 38% of all lead, have an average life of 4 years, a growth rate of 4% per year, and are recycled with an efficiency of 80%. Architectural lead accounts for 16% of total consumption. The lead on buildings has an average life of 70 years after which 95% of it is recycled. What is the fractional contribution of recycled lead from each source to current supply?