14 more billionaires just joined Warren Buffett and Bill Gates in pledging to give away most of their money

Fourteen billionaires and billionaire couples have committed to donating most of their fortunes to philanthropic causes, joining Warren Buffett and Bill Gates in signing the Giving Pledge, the organization announced Tuesday.

The new members of the Giving Pledge - a global organization started by Buffett and Bill and Melinda Gates to encourage the world's wealthiest to donate a majority of their riches - hail from eight countries and built a diverse array of businesses. They include: private equity titan Dean Metropoulos; Dagmar Dolby, the wife of audio systems giant founder Ray Dolby; Leonard H. Ainsworth, the Australian founder of a casino gaming machines company; and Sir Stelios Haji-Ioannou, the Cypriot founder of easyJet who now lives in Monaco.

"Philanthropy is different around the world, but almost every culture has a long-standing tradition of giving back,"said Melinda Gates, co-chair of the Bill & Melinda Gates Foundation, in the Giving Pledge announcement. "Bill and Warren and I are excited to welcome the new, very international group of philanthropists joining the Giving Pledge, and we look forward to learning from their diverse experiences."

Here are the 14 new members and their home countries, according to the announcement:

1. Leonard H. Ainsworth - Australia

2. Mohammed Dewji - Tanzania

3. Dagmar Dolby - United States

4. DONG Fangjun - People's Republic of China

5. Anne Grete Eidsvig and Kjell Inge Røkke - Norway

6. Sir Stelios Haji-Ioannou - Monaco, Cyprus

7. Nick and Leslie Hanauer - United States

8. Iza and Samo Login - Slovenia

9. Dean and Marianne Metropoulos - United States

10. Terry and Susan Ragon - United States

11. Nat Simons and Laura Baxter-Simons - United States

12. Robert Frederick Smith - United States

13. Harry H. Stine - United States

14. YOU Zhonghui - People's Republic of China

The new additions bring this rarefied philanthropy club's total membership to 168 pledgers from 21 different countries.

Buffett and Gates, who founded the Giving Pledge in 2010, remain among the few richest on earth - with fortunes of $73.5 billion and $95.5 billion, respectively - despite being the most generous. The Gates' lifetime giving now exceeds $32 billion while Buffett's exceeds $25 billion, according to Forbes.