Around is a fine translation, and it send the right message across. Nobody writes siting around a book, nobody would think that. But "approximately " would be the best word to use. "About" can actually be confusing, because it could mean that you write something related to a book every year, especially if you use "a" instead of "one", and " every" instead of "per"
Circa is so easy to remember as around. It is so close to circle. Children go around a circle Circa 1540, a phrase used by scholars, means the year is uncertain--around 1540. We round numbers up or down.
As for writing a book per year, consider Alexander McCall Smith or Janet Evanovich who each write a popular detective series. My argument for around, which I suppose is from Anglo-Saxon, is the easy cognate circle to circa. Too many years of reading. Approximately however does work nicely in this sentence.
"Quasi" carries a connotation of falsity in English.