This is US only. International shipments for ASUS and Lenovo have skyrocketed way past Apples sales.
ASUS was + 39 % and Lenovo was +19%
In most countries, Apple is irrelevant as a computer brand. They don't sell business systems, they don't sell business software and they're too expensive for the majority of home users.
Also, the general consumer behavior is different outside the US - most people don't buy (expensive) gadgets as an accessory or status symbol. The majority still sees computers and phones and TOOLS, not as ends in themselves.
It's hard to sell a 13" MacBook Air for EUR 1250 when you can have an Acer Ultrabook with the same screen size for EUR 599. And this is a market where Apple is ONLY two times as expensive as the competition.
15.4" notebooks with Core i3 CPUs that are more than good enough for all everyday tasks can be bought for 400 Euros. Sure, you don't get the Apple Unibody design, it's all plastic. But you already get more horsepower for that money than most people ever need for their Office and web browsing purposes. 15" MacBook Pros on the other hand start at 1879 Euros in Germany - that's 4.5 times the price for the cheapest 15" model that Apple offers.
Yeah, I know the bla bla about when you compare, you need to compare on the same level. Well, I actually did that. I compared the CHEAPEST Acer model with the CHEAPEST Apple model in the same class. Duh!
If I spend the same money on, let's say, a Sony Vaio, among other things I get a much faster CPU, longer battery life, twice the RAM and an SSD disk instead of the slow hard disk that the Macbook Pro for that price only has.
You need some very convincing sales arguments to get NORMAL people to spend that amount of money on a computer, and then you need even more convincing arguments to talk them into spending the same amount of money on LESS hardware.
And again, let's not forget this tiny little detail here: Apple have turned themselves into a consumer brand. That's an awful lot of money for stuff that you will only use at home to surf the web and check the updates from your virtual "friends" on Facebook. And the reality is that those webpages that Safari/Chrome/Firefox display look exactly the same on all supported operating systems (which in the case of Chrome and Firefox include Linux and Android and not just OS X and Windows).