During the its fiscal 2010 second quarter that ended March 27, Apple saw its retail store chain increase revenue by 22%. That’s up 38% year-over-year.

Apple had an average of 284 stores open during the quarter. The stores saw 47 million visitors in the second fiscal quarter of 2010 as compared to 39.1 million in the second fiscal quarter of 2009. The average revenue per store was $5.9 million, compared to $5.5 million in the 2009 quarter.

Apple will open 40-50 new retail stores before the end of the year. Half of them will be international stores, with locations including London, Paris and Shanghai. The latter will get two stores, and Apple plans on having 20 retail stores in China by the end of 2011.

The retail stores sold approximately 606,000 Macs. And, as always, in talking with analysts about the fiscal results, Apple Chief Financial Officer said that half of those sales are to folks who’ve never bought a Mac before.