Many punishments imposed by Sharia are themselves a form of violent jihad if measured by Western sensibilities.It is impossible to know exact numbers because a key doctrine in orthodox Islam is taqiyya, lying and deception (aka dissimulation) to mislead others, hide true intent, in order to defend the individual Muslim or Islam.
The only thing keeping US Muslims from more overtly supporting Jihadi violence is their minority status in this nation.
As their numbers or concentrations in urban areas increase, you will see more overtly violent activity.
(See also "Moderate" Muslims.)Does it matter how many "peace-loving" Muslims there are if they are all led by or beholden to radical leaders? Because "stealth" Jihad, or political Islam which some call "Islamism," is more effective than violent Jihad in a liberty embracing country like the US. An uneducated guess would be well over 50% of Muslims in the US.
Here is an interesting perspective comparing how the few (a relative term - in the case of Islam, "few" could mean a few million) activists of movements throughout history can wreak havoc on the world. I would like informed sources to advise on this point.
One doesn't necessarily have to be a Jihadi to be working toward Sharia Law and the domination of US culture by Islamic norms.
This is the subject of Robert Spencer's book, Stealth Jihad. I've provided several estimates within this web site ranging from 7 to 25% as shown above on this page.
I've been asked by serveral people what the source of my information is.
Here is the answer I've provided: Where I've provided numbers on the web site, I've provided underlined links in many cases - e.g. Where links are not provided, estimates are based on Islamic doctrine, Islamic history, and current events concerning Islamic populations.
Here's how I define radical Islam based on 10 years of observation and study: Muslims the media calls "radicals" are the militant arm of Islam, aka violent jihadis - for example ISIS, al Qaeda etc. Muslims the media calls "moderates" for the most part do not show themselves to support radicals, but many are likely to have sympathies for radicals by privately supporting them politically, financially, logistically, or socially.
Consequently there is some unknown number of what the media calls "moderate" Muslims who are apostate. To defend his beliefs, he has to disregard 60% of the Islamic trilogy, including much of the Qur'an.
Google "Political Islam" to see the percentage of the Islamic texts that support hatred of the infidel, kafir, Jews, or support for various acts of violent jihad.