#Years

year<-c(1800,1810,1820,1830,1840,1850,1860,1870,1880

,1890,1900,1910,1920,1930,1940,1950,1960,1970

,1980,1990,2000,2010,2020)

#The population

pop<-c(3800,4800,7500,28000,212300,397700,749100,

1200000,1600000,2100000,2400000,2810173,

3668412,4842325,5256106,6371766,7823194,

8875083,9262078,9295297,9938444,9883640,10077331)

use R software

Fit data use "SSgompertz" function on this model, a simplified Gompertz functionAsym*exp(-b2*b3^x),whichonly has 3 parameters. Use this one instead, with starting values close to the values obtained from the selfstarter, or from trial and error.