(CNN) -- No-one has been awarded the world's most valuable prize, the $5 million Ibrahim Prize for Achievement in African Leadership, which was due to be announced Monday.
For the third time in six years, no African leader has been deemed worthy of the prize, awarded by Sudanese billionaire Mo Ibrahim's foundation.
"The Prize Committee reviewed a number of eligible candidates but none met the criteria needed to win this Award. The Award is about excellence in leadership." the Mo Ibrahim Foundation Prize Committee said in a press release.
The prize is a $5 million award paid over 10 years and $200,000 annually for life after that.
It is awarded to democratically elected leaders who have stepped down in the past three years after serving their constitutionally mandated term, and have demonstrated "excellence in office."
Ibrahim, chairman and founder of the Mo Ibrahim Foundation, said: "Since we launched the Prize six years ago, we have had three winners, and three years without."
Last year's winner was President Pedro Verona Pires of Cape Verde for his "vision in transforming Cape Verde into a model of democracy, stability and increased prosperity."
Other previous winners have been Joaquim Chissano of Mozambique in 2007 and Festus Mogae of Botswana in 2008. Nelson Mandela was made the honorary inaugural Laureate in 2006.
In 2009 and 2010 there was no winner.
In a report on African governance released by the Mo Ibrahim Foundation Monday to coincide with the prize, Nigeria moved into the bottom 10 countries on the continent for governance for the first time. It was ranked 43rd out of 54 countries based on 88 indicators taking in factors such as human rights, rule of law, development, personal safety, participation in the political process, infrastructure, welfare, health and education.
The Ibrahim Index of African Governance (IIAG) -- an annual study measuring accountability and good governance in 52 out of 54 African nations -- found four of the continent's powerhouses, Nigeria, Kenya, Egypt and South Africa, have declined in quality of governance since 2006.
Abdoulie Janneh, former Executive Secretary of the UN Economic Commission for Africa and Board Member of the Mo Ibrahim Foundation said in a press release: "Given the vast natural and human resources of these four regional powers, these governance results are a concern.
"Each of these countries plays a key role in the economic and political landscape of the continent. To continue to optimally play this role requires a sustained commitment to balanced and equitable governance."
Nigeria, Kenya, Egypt and South Africa were all deemed to have deteriorated in their safety, rule of law, participation for citizens and human rights.
Claims of corruption in Nigeria and Kenya have been common in recent years, with Transparency International ranking the two countries 143 and 154 respectively out of 183 nations for corruption.
South Africa and Kenya meanwhile also registered a drop in sustainable economic opportunity.
The report uses data from 2000 to 2011 and does not take into account changes in Egypt, Libya and Tunisia since the Arab Spring. The report's authors used data from hundreds of sources but said a lack of data had hindered it.
Ibrahim said in a press release: "Good governance is about harnessing a country's resources to achieve the results any citizen living in the 21st century has a right to expect. One of Africa's biggest leadership and governance challenges going forward is to master its own robust statistical system. Political sovereignty begins with data autonomy."
The report said there was an overarching trend towards more inclusive and representative leadership since 2000, with improvements in 11 out of 14 of its subcategories.
Significant improvements in the rule of law were registered in the formerly war-torn nations of Liberia and Sierra Leone, while Angola, Guinea and Liberia made major strides in human rights.
Other countries to record strong performances in areas such as human development and sustainable economic performance included Rwanda, Mauritius and Zambia. Tanzania has climbed the IIAG's rankings over the past six years, making it into the top 10 for the first time.
Across the continent the study noted particularly high improvements in gender equality in all regions bar west Africa.
Mary Robinson, former president of Ireland and Board Member of the Mo Ibrahim Foundation said, "Africa's women have the capacity to bring about remarkable change and therefore equity and equality between men and women is in the strategic interests of African leaders and governments."
Earlier this month, the foundation awarded Archbishop Desmond Tutu a one-off $1 million special prize for his lifelong commitment towards "speaking truth to power," -- a trait emphasized throughout South African apartheid and more recently in his call for Tony Blair and George W. Bush to "made to answer" at the International Criminal Court for their role in the Iraq war.
Which African leaders do you think are worthy of the prize? Tell us in the comments below.