1. USA
2. Austria (1971)
3. France (1971)
4. Spain (1971)
5. West Germany (1971)
6. Czechoslovakia (1971)
7. Canada (1976)
8. Mexico (1982)
9. Bahamas (1985)
10. Norway (1994)
11. Netherlands (1998)
12. Belgium (1999)
13. Germany (2003)
14. Italy (2003)
15. United Kingdom (2003)
16. Morocco (2004)
17. Vatican City (2004)
18. Czech Republic (2005)
19. Slovakia (2005)
20. Scotland (2007)
21. Switzerland (2007)
22. Ireland (2008)
23. Hungary (2009)
24. Belize (2009)
25. Honduras (2009)
26. Poland (2009)
27. Liechtenstein (2011)
28. Jamaica (2011)
29. Maldives (2011)
30. French Polynesia (2012)
31. Singapore (2012)
32. South Africa (2013)
33. United Arab Emirates (2013)
34. Portugal (2013)
35. Albania (2014)
36. Bosnia and Herzegovina (2014)
37. Bulgaria (2014)
38. Croatia (2014)
39. Kosovo (2014)
40. Macedonia (2014)
41. Monaco (2014)
42. Montenegro (2014)
43. Serbia (2014)
44. Slovenia (2014)
45. Argentina (2014)
46. Cambodia (2014)
47. China (2014)
48. Japan (2014)
49. Korea South (2014)
50. Malaysia (2014)
51. Qatar (2015)
52. India (2015)
53. Guatemala (2015)
54. El Salvador (2015)
55. Brazil (2015)
56. San Marino (2015)
57. Costa Rica (2015)
58. Columbia (2015)
59. Zambia (2015)
60. Zimbabwe (2015)
61. Namibia (2015)
62. Botswana (2015)
63. Nicaragua (2015)
64. Chile (2016)
65. Ecuador (2016)
66. Andora (2016)
67. Oman (2016)
68. Panama (2016)
69. Barbados (2016)
70. St Kitts (2016)
71. Antigua (2016)
72. Dominica (2016)
73. St Lucia (2016)
74. Grenada (2016)
75. Thailand (2017)
76. Myanmar (2017)
77. Laos (2017)
Booked trips:
2017: Trinidad & Tobago, Denmark, Estonia, Russia, Finland, Sweden
2018: Haiti, Dominican Republic, Taiwan, Indonesia, Greece, Turkey
I don't count several territories I've visited and must spend at least some time in each country sightseeing.