In this task you are given a list of numbers and you need to find the average of each two consecutive values. The average of two numbers a and b is calculated as: (a + b) /2. The output should be a list of the averages of each two consecutive values. A list is presented with two brackets and comma-separated values, like: [1,2,3].
[-91, 16, 62, 42, -91, -73, -93, 1, -78, 58, 59, 20, 77, 78, -31]