There should be also a discussion of what constitutes "tax fraud", because in my home country you can go to jail for tax fraud, but countless tv / sports personalities, people who were making millions of euro a year and where declaring residency in Monaco even if they were live from tv studios inside the country each day, were simply fined and then settled in court.
People who are in prison︀ for tax fraud are mostly people who sold goods into the country evading VAT by︁ setting up triangolations with other countries, like some famous mobile phones websites. What constitutes tax︂ fraud is more at the corporate level and related to the internal market, rather than︃ at the personal level. But that also depends on how people in the country perceive︄ the crime, in my home country if you f**k the state, you are a hero,︅ in Denmark I guess it's different. In any case I would agree that I think︆ it's hard to go to jail as a denmark citizen for tax fraud in bulgaria,︇ I would be morw worried about going to jail in Denmark.
While in the USA︈ you definitely go to Jail for tax evasion, it's 5 years.