According to South African President Jacob Zuma, anti-apartheid leader and Nobel Peace Prize winner Nelson Mandela "continues to engage with family" during his hospital stay; however, he remains in critical condition.

The former South African president's doctors say although his condition is still considered serious, health improvements have been sustained, the Associated Press reported.

The past year has been a trying time for the iconic leader's family, seeing as this is the fourth time Mandela has been admitted to the hospital for a reoccurring lung infection.

Nelson Mandela's Health Timeline:

1990 - Mandela is released from Robben Island prison where he contracted tuberculosis during his stay.

2001 - Diagnosed and treated for prostate cancer.

January 2011 - Spends two nights in Johannesburg hospital where he is diagnosed with chest infection.

February 2012 - Spends one night in hospital with abdominal complications.

December 8, 2013 - Undergoes gallstone surgery to repair lung infection.

December 26, 2013 - Released from hospital after successful operation.

March 27, 2013 - Admitted to hospital after signs of lung infection point to pneumonia.

April 29, 2013 - Mandela makes first television appearance since hospitalization, looking malnourished.

June 8, 2013 - Readmitted to hospital under "serious but stable" condition.

June 16, 2013 - Health sees sustained improvement.