library(data.table)
>
> dat <- data.table(x = sample(c(10, 16, 22, 28, 34, 40), 20, replace = TRUE),
+                    y = sample(seq(0.5, 19.5, by = 1), 20, replace =  TRUE))
>
>
> TempData <- dat[, .(Counting = .N), .(x, y)][order(x, y)]
> TempData <- TempData[, Counting := cumsum(Counting), x]
>
> TempData <- dat[, .(Number = .N), x][TempData, on = "x"]
>
> TempData <- TempData[, result := Counting / Number]
> TempData[, `:=`(Number = NULL, Counting = NULL)]
>
> A<-as.matrix(TempData)
> A
       x    y    result
 [1,] 10  8.5 0.5000000
 [2,] 10 12.5 1.0000000
 [3,] 16  0.5 0.2500000
 [4,] 16  5.5 0.5000000
 [5,] 16 12.5 0.7500000
 [6,] 16 17.5 1.0000000
 [7,] 22  5.5 0.5000000
 [8,] 22  7.5 1.0000000
 [9,] 28  0.5 0.2000000
[10,] 28  2.5 0.4000000
[11,] 28  8.5 0.6000000
[12,] 28 18.5 0.8000000
[13,] 28 19.5 1.0000000
[14,] 34  2.5 0.2500000
[15,] 34 10.5 0.5000000
[16,] 34 11.5 0.7500000
[17,] 34 13.5 1.0000000
[18,] 40  0.5 0.3333333
[19,] 40  3.5 0.6666667
[20,] 40  8.5 1.0000000
>