Why do Fords only have 1 reverse light?

All the Fords i have seen lately only seem to have 1 reverse light on the back left of the car. Does anyone know why this is?
Answers:
A single bulb circuit is cheaper to engineer and mass produce for a range of different models.

You will probably find that most Fords only have 1 rear fog light as well- for the same reasons.

In addition, this allows Ford to make asymmetric light clusters which reduces complication when ordering parts. Asymmetric light clusters can also be more space efficient, as they are one lens down on symmetrical light clusters.
Its much cheaper then two
thay only have one light because it cuts down on the cost of there cars which are over price anyway buy a jap car there better
They don't have only 1 reverse light. For example, Ford Mondeos in the UK have 2 reversing lights.
because they're cheap and cheerful!!
two reasons the law does not say you need two and the other is simply money $$ why put in two when you can save and put in one
Reverse on the nearside, fog on the offside
So we don't blind the Chevy guys when we back up to let them catch up with us
I have 2 in my mustang. Don't know about anyone else.
It varies depending on where you live. In a lot of europe reversing lights aren't a legal requirement (they are in the UK) so you'll find a lot of UK cars have one fog light and one reversing light. Go abroad to other european countries and the same model will normally carry two fog lights instead. You'll see similar occuraces on GM / Vauxhaul / Opel cars where they are sold in a multitude of countries.

Country specific cars (like the mustang, which has almost no sales outside the US) don't need to have this interchangeability.
My 95 ranger definitely had two, one on each side.

Could one of your lights have simply burned out? Or is one light just not turning on when you shift into reverse?
I've got TWO on my Honda, but then it's a decent car.
In the US and Canada, all of them must have 2 bulbs.. It may look like one sometimes but they must have 2 seperate bulbs at least .

Elsewhere, as someone said, it may not matter