The following is a description (slightly modified) from Dr. Peter Hammond's book: Slavery, Terrorism and Islam: The Historical Roots and Contemporary Threat. Link
As long as the Muslim population remains around 1% of any given country they will be regarded as a peace-loving minority and not as a threat to anyone. In fact, they may be featured in articles and films, stereotyped for their colorful uniqueness.
At 2% and 3% they begin to proselytize from other ethnic minorities and disaffected groups with major recruiting from the jails and among street gangs [Europe, Australia, USA and Japan]. Six percent of US prison inmates are Muslim. Like any other minority, they wont integrate, but work to build their own separate community.
From 5% on they exercise an inordinate influence in proportion to their percentage of the population. South Africa's Muslim population is 2%, but they control 35% of the businesses, a large percentage of the banks and have five Cabinet seats while Christians (77% of the population) have none.
They will push for the introduction of halaal (clean by Islamic standards) food, thereby securing food preparation jobs for Muslims. They will increase pressure on supermarket chains to feature it on their shelves (along with threats for failure to comply).
At this point, they will work to get the ruling government to allow them to rule themselves under Sharia; Islamic Law. The ultimate goal of Islam is not to convert the world, but to establish Sharia law over the entire world.
When Muslims reach 10% of the population, they will increase lawlessness as a means of complaint about their conditions. (Ei: car-burnings in France last October.) Any non-Muslim action that offends Islam will result in uprisings and threats.
After reaching 20% expect hair-trigger rioting, jihad militia formations, sporadic killings and church and synagogue burning (India, Mindanao, Philippines).
At 40% you will find widespread massacres, chronic terror attacks and ongoing militia warfare [Indonesia].
From 60% you may expect unfettered persecution of non-believers and other religions, sporadic ethnic cleansing (genocide), use of Sharia Law as a weapon and Jizya (infidel tax). (Sudan, Kosovo, Lebanon and Egypt).
After 80% expect State run ethnic cleansing and genocide [Western Papua (New Guinea), Iran, Biafra, Turkey and North Nigeria].
100% will usher in the peace of "Dar-es-Salaam" - House of Peace - as in Saudi Arabia, Libya and Yemen.
Get out of our country!!! Of course that guy will end up getting enough money to by a Happy Meal after the Museum and Lawyers get their cut.