Given the task definition and input, reply with output. 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].

[-90, -99, 53, 30, -78, -33, -84, 67, 91, -75, -40, 7, 94, 35, 15]

[-94.5, -23.0, 41.5, -24.0, -55.5, -58.5, -8.5, 79.0, 8.0, -57.5, -16.5, 50.5, 64.5, 25.0]