… The 90-percentile values for the three ten-year periods (1986-1995, 1996-2005 and 2006-2015) at LAWA monitoring sites for which data is available for at … and more to inputs. Comparing the first two ten-year periods 1986-1995 and 1996-2005 reveals a sharp drop in phosphorus and ammonium concentrations, both in terms … The 90-percentile values for the three ten-year periods (1986-1995, 1996-2005 and 2006-2015) at LAWA monitoring sites for which data is available for at …