Sudan has around 25–30 universities; instruction is primarily in Arabic or English. Education at the secondary and university levels has been seriously hampered by the requirement that most males perform military service before completing their education. In addition, the "Islamisation" encouraged by president Al-Bashir alienated many researchers: the official language of instruction in universities was changed from English to Arabic and Islamic courses became mandatory. Internal science funding withered. According to UNESCO, more than 3,000 Sudanese researchers left the country between 2002 and 2014. By 2013, the country had a mere 19 researchers for every 100,000 citizens, or 1/30 the ratio of Egypt, according to the Sudanese National Centre for Research. In 2015, Sudan published only about 500 scientific papers. In comparison, Poland, a country of similar population size, publishes on the order of 10,000 papers per year.