Apple has more than $205bn of cash in the bank, the company revealed on Tuesday as its chief executive Tim Cook said the firm had made more than $234bn in 2015, making it its “most successful year ever”.

The California company now has more money in the bank than the Czech Republic, Peru and New Zealand make in gross domestic product (GDP) a year, according to World Bank statistics. Apple’s cash balances increased by $2.8bn in the last three months alone.

Apple sold 48m iPhones worth $33.2bn in its latest quarter – an increase of 36% on the same period last year and more than the total sales achieved by both Microsoft and Facebook over the same period.

Its quarterly profit came in at $11.1bn, 31% more than in the fourth quarter of 2014. Sales were up 22% in the three months to 28 September to $51.5bn.

“Today we’re reporting a very strong finish to a record-breaking year, ” Cook said. “We are heading into the holidays with our strongest product lineup yet.”

Apple, which is already the world’s most valuable company, worth $657bn, said predicted sales would increase further to between $75.5 and $77.5bn in its current quarter as only the first weekend of new iPhone 6S sales were captured in the previous three months.

“We think we can grow iPhone (sales) during the December quarter,” chief financial officer Luca Maestri said. The average iPhone now sells for $670, an increase of $67 on the previous quarter.

Sales in China doubled compared to the same period last year, to $12.5bn, and some analysts predict that China could overtake the US to become Apple’s biggest market.

While the iPhone continues to soar, iPad sales dropped for the seventh consecutive quarter and were down 20% compared to the 2014 fourth quarter. The company did not state how many Apple Watches it has sold.

Apple’s shares, which have fallen by about 15% from a peak of $133 in July, increased by 0.6% to $114.5o in after-hours trading in New York on Tuesday.

• This article was amended on 28 October 2015 because an earlier version said Apple sold 48bn iPhones in its latest quarter. This has been corrected to say 48m iPhones.