Mustapha said this on Wednesday in Abuja in an interview with newsmen in reaction to the victory of Buhari at the poll.
He said the victory of the president was exciting because it was a victory for democracy and Nigerians.
The people of Nigeria have spoken through their votes and reconfirmed their faith and trust in the person of President Muhammad Buhari.
Having seen how he governed the country in the past three and half years, Nigerians have every reason to be grateful of his re-election.
It was an election where we did not campaign with promises, our campaign was based on our score cards, he said.
According to him, we were able to tell the people of Nigeria where we were when we took over in 2015 and what we have been able to achieve.
He said that the president had in 2015 anchored his campaign on three platforms security, diversification of the economy and fight against corruption.
The SGF said that about 17 local government areas were under the territorial control of Boko Haram in the North-East when the president took over.
But today, the whole areas have been liberated with minor challenges as it is expected in that kind of insurgency situation.
Relatively, there have been restoration of peace and calm in the North-East although, we still have some spots of problem in the North-West, and North-Central zones of the country.
It has been the resolve of the president to do everything to ensure that every part of the country is secured before it can be governed, he said.
He said that the Buhari administraiton had also grown the population of rice farmers from 4 million to over 12 million.
Mustapha said that the social investment policy of the administration, the conditional cash transfer, school feeding programme and the N-Power programme had impacted positively on the lives of Nigerians.
The News Agency of Nigeria (NAN) reports that the Independent National Electoral Commission (INEC) had declared President Muhammadu Buhari, candidate of the All Progressives Congress (APC), winner of the 2019 presidential election held on Saturday, Feb. 23.
Buhari was returned re-elected having polled 15,191,847 votes, winning in 19 states, to defeat other 72 candidates including Atiku Abubakar, the Candidate of the Peoples Democratic Party (PDP), who scored 11, 255,978 votes and won 17 states and the FCT, to occupy the second position.
The Chief Retuning Officer and INEC Chairman, Prof. Mahmood Yakubu, announced the result at the national collation centre on Wednesday morning.
Yakubu said that Buhari was declared re-elected, having met the constitutional requirements.