According to Todd M. Johnson and the World Christian Encyclopedia, from AD33 to 1914 24 million Christians died for their faith. Just since AD1915 an additional 45 million Christians died for their faith in Christ. This means that more Christians were martyred in the 1900s than all the previous centuries combined.
The top five most persecuted countries in the world according to Open Doors International are North Korea, Saudi Arabia, Iran, Maldives, and Bhutan.