Many or none it depends on the persons qualities and etc.
Many people who have personally experienced miracles do believe that God can and does perform healing miracles in answer to prayer. Often the answer to prayer is different from what we want because God has another plan for the person. Thousands believe that the person pulled alive from the rubble a full month after the Haitian earthquake was definitely a miracle!
First of all, the saints do not perform miracles. The miracles are performed by God at the request of the saint. Each individual case is based on its own merits. Usually 2 miracles are required, one for beatification and one for canonization. If the person died as a martyr, one or more miracles may be dropped. Other things can also be taken into consideration such as bilocation. incorruptibility, stigmata, heavenly perfume, etc.
A person who is beatified is a person who it is proved that during his life interceded to God for in someone else. This is a process that involves a lot of research because miracles can't be medically proven and takes many years. After it is beatified, if it is proved that he interceded to God for another miracle, it is investigated to canonize him. One miracle make a people blessed, two or more miracles make them saints.
9 miracles
There is many miracles , but the greatest miracle is The Quran
miracles and wonders
Bernadette was responsible for many, many miracles and they continue even today. However, the Church must investigate and verify a number of miracles (today I believe it is two) before a person can be beatified and canonized a saint. Rather than listing the miracles here that were accepted by the Church in the cause of St. Bernadette I have inserted a link below that describes her complete canonization process and gives vivid accounts of the miracles that supported her cause.
Miracles of Life has 278 pages.
Miracles were not required for declaring a person a saint in the early years of Chrisitianity. The person would have been declared a saint by popular acclamation to a bishop based on the lives and merits of the candidate. This was especially true if the person died the death of a martyr as it was felt that making this ultimate sacrifice for Our Lord would be an automatic designation of that person as a saint. Even today, miracles are not always a requirement for canonization, especially in the case of martyrs.
Imam Ali has performed many many miracles by the order of the Almighty. There are atleast 250 miracles on record, including bringing the dead to life.
He has done 8 miracles
The Men Who Explained Miracles has 192 pages.