https://archive.epa.gov/ocir/Archive/web/pdf/annual101.pdf monthly 1.00 https://archive.epa.gov/ocir/Archive/web/pdf/annual103.pdf monthly 0.80 https://archive.epa.gov/ocir/Archive/web/pdf/annual104.pdf monthly 0.80 https://archive.epa.gov/ocir/Archive/web/pdf/annual105.pdf monthly 0.80 https://archive.epa.gov/ocir/Archive/web/pdf/annual106.pdf monthly 0.80 https://archive.epa.gov/ocir/Archive/web/pdf/summaries00.pdf monthly 0.80 https://archive.epa.gov/ocir/Archive/web/pdf/nutrient_trading_and_water_quality.pdf monthly 0.80 https://archive.epa.gov/ocir/Archive/web/pdf/summaries99.pdf monthly 0.80 https://archive.epa.gov/ocir/Archive/web/html/104thcongress.html monthly 0.80