According to Mayor Sofia is a Reading City Promoting Reading

Sofia is a reading city and promoting reading for me has always been a cause, Mayor of Sofia Yordanka Fandakova said at the opening of the Spring Book Fair at the National Palace of Culture, Focus News Agency reports.
"Only a few days after 24 May, the Day of Bulgarian Education and Culture, the largest spring book exhibition in Bulgaria opens in Sofia - the traditional Spring Book Fair. Sofia is a reading city - there is no doubt about it," the mayor said, adding that this has been evident from the statistics of books purchased and borrowed from libraries in recent years. "The time has come for boutiques in the most expensive streets and shopping centres to close and bookshops to open instead. Not long ago the opposite was happening," Fandakova said.
"Promoting reading for me has always been a cause. Reading means more literacy, greater imagination and higher intelligence, and that's what we want for our children," the mayor said. She noted that according to data from the biggest publishers, about 4 million books had been sold since the beginning of the year, up 6% compared to last year.