I really need to get out of the country more often

After I wrote about my goal of visiting the world's 25 smallest countries, I decided to make a tally of all the countries I've visited and when I visited them. For somebody who likes to travel, this list is remarkably sparse:

Antigua and Barbuda: 
2015

Austria: 
2002

Barbados:  
2015

Belize:  
2006

Canada:
1974, 1980, 1982

Czech Republic:
2002

Ecuador: 
1988, 1989, 1990, 1993, 2001

Germany: 
2002

Ireland:
1985

Japan: 
2005

Mexico: 
1979, 1983, 1986, 1987, 1989, 1995, 1997, 1998, 1999, 2000, 2003, 2004, 2005, 2006, 2007

The Kingdom of the Netherlands:

The Netherlands: 
2002, 2006

Aruba: 
2014

 St. Maarten:  
2015

St. Kitts and Nevis:  
2015

St. Lucia:  
2015

United Arab Emirates: 
2006, 2008, 2012

The United Kingdom:

England:
1985

Scotland:
1985

 Wales:
1985


Airport stopovers (where I do not leave the terminal) do not count. Border crossings, airport stopovers where I do leave the terminal, and cruise ports of call do count, and are italicized. I broke out the United Kingdom and The Kingdom of the Netherlands into their constituent countries but I don't count them separately as they are not fully sovereign.

That's 16 out of 206 sovereign (or de-facto sovereign) nations, or 7.7% percent. That's pretty pathetic.

I need to redouble my efforts to see more of the world. Where shall I travel next?

(Flag source: World Flag Database)