“…The statistics on IN 1 of LO 7 in the period 2017-2020 were used to build the original value chain as follows: X (0) = (1, 421, 715, 1, 625, 789, 1, 947, 165, 2,346,510) The authors use the cumulative addition method to build the value chain of X (1) : 421,715,3,047,504,4,994,669,7,341,179) The authors use the value chain of X (1) to calculate the mean Z (1) : With the coefficients a, b, the authors built the equation of the GM (1, 1) model:…”