Your for loop iterates over 71 results, but your array has only the length 70.
You may overwrite variables in the memory behind the array.
You can use else instead of else if (i >= 70 * 0.1) because it is just the negation of the if (i < 70 * 0.1). In the else case (i >= 70 * 0.1) is always true.
What is the type of myVariable? ...