Find the logistic function to model for the expected life span of people in a country for certain birth years after year 1900 is given in the table. Birth Year: 1920 1930 1940 1950 1960 1970 1975 1980 1987 1988 1989 1990 1992 Life Span (years): 63.3 69.3 742 78.0 80.9 83.0 83.9 84.6 85.4 85.5 85.7 85.7 85.9 Birth Year: 1994 1996 1998 1999 2000 2001 2002 2003 2004 2005 2010 2015 2020 Life Span (years): 86.1 86.3 86.4 86.5 86.6 86.6 86.7 86.8 86.8 86.9 87.1 87.4 87.5 y= __ / 1+ ___e^__x Use integers or decimals for any numbers in the expression. round to three decimal places as needed