Apple has sold more iPads in the last four years than it sold iPhones in the first four years they were available.

And yet, despite these amazing figures, Apple's tablet business is suffering.

In the last three months, sales have dipped a huge 12% compared to the same period in 2013, as increased competition and a much slower refresh rate, means the market is reaching saturation point.

So what's Apple's answer? The iPad Air 2 which goes on sale this week and it thinner, lighter, and more powerful than ever before - but is this enough to reverse the decline in sales?