In this task, you're given a passage, further information available on a particular linked term from the statement, and an answer term. Your job is to generate a question that can use the information provided to obtain the given answer. You should use the information on both passage and link information to create the question. Note that the answer to the question should be exactly the given answer, and if the answer is none, the answer to the question shouldn't be obtainable from the passage or linked information.

Passage: Following the death of military dictator and de facto ruler of Nigeria, General Sani Abacha in 1998, his successor General Abdusalami Abubakar initiated the transition which heralded Nigeria's return to democratic rule in 1999. The ban on political activities was lifted, and political prisoners were released from detention facilities. The constitution was styled after the ill-fated Second Republic — which saw the Westminster system of government jettisoned for an American Presidential system. Political parties were formed (People's Democratic Party (PDP), All Nigeria Peoples Party (ANPP), and Alliance for Democracy (AD)), and elections were set for April 1999. In the widely monitored 1999 election, former military ruler Olusegun Obasanjo was elected on the PDP platform. On 29 May 1999, Obasanjo was sworn in as President and Commander-in-Chief of the Federal Republic of Nigeria.
 Link Information: his successor General Answer: 1
What was the age difference between the dictator who died in 1998 and the person who replaced him?