Apple just handed its annual report in to the SEC, revealing that the company laid out an extra billion dollars on Research and Development this year. But despite jumping from $2.4 to $3.4 billion dollars, R&D spending stayed flat as an overall percentage of revenue — a scant 2.2 percent — thanks to a 45 percent increase in sales, to $156 billion. In comparison, rivals like Google and Microsoft spend around 15 percent of revenues, and Samsung sits in between at around 6 percent.

Apple says it racked up the billion-dollar increase by hiring more researchers. A year ago we reported that the company was expanding research efforts in Israel, which is likely responsible for a big share of the bump. The addition is part of a hiring increase across the board — as pointed out by The Next Web, Apple’s headcount grew from a total of 60,400 full-timers in 2011 to 72,800 in 2012.

During the year the company also increased its floor space from 13.2 to 17.3 million square feet as it added 33 new retail stores, fueled by retail sales growth of 33 percent. And land holdings are up as well, going from 584 acres in 2011 to 1,077 acres this year as Apple announced plans to build a data center in Prineville, Oregon as well as add extra solar energy capacity at its Maiden, North Carolina center. Perhaps the most surprising figure, however, is a 94 percent increase in Japanese sales over the year, as the iPhone became the top-selling handset in the country despite the long dominance of domestic brands like Sharp and Fujitsu-Toshiba.