random spawn yield

so im doing a random spawn so an object randomly spawns so far its worked but i wanna make it so one spawns every five seconds how would i do tht? i figure i would need a yield but can someone give me an eample script? heres what i have so far:

var Cube:Transform;
function Update ()
{
  var position = Vector3(Random.Range(-10, 10), 1, Random.Range(-10,10));
  Instantiate(cube, position, Quaternion.identity);
}

InvokeRepeating is better than using yield in this case:

var spawnTime = 5.0;

function Start () {
    InvokeRepeating("Spawn", .01, spawnTime);
}

function Spawn () {
    // instantiate something here
}