This question can be answered in few ways. If you go with the Vedas which says that the ENTIRE WORLD IS ONE FAMILY. It also says THERE ARE MANY PATHS TO GOD. Using these 2 mantras those who refer to themselves as Hindu don’t aim at converting people or expanding the teachings by force. One has to find there own path to Bhagwan (God). This means other religions are equally relevant in the Hindu eye. Hindus aim is not to convert but to understand and show respect to all living beings. The key is to live life by the Ahinsa (Ahimsa) principal.
Below is the top 10 countries with Hindu population where there are more than million+ Hindus.
1. India
2. Nepal
3. Bangladesh
4. Indonesia
5. Pakistan
6. Sri Lanka
7. United States
8. Malaysia
9. Myanmar
10. United Kingdom
There are groups of Hindus who follow the ISKON teachings who make there goal at spreading the word of Swami Prabhupad which is centered around the Avtar of Bhagwan Krishn.