Religion that is not spiritual falls into the realm of secular religion. There isn't many secular religions, and the ones that exist have very few adherents. On the other hand, spirituality without religion seems to be prevailing. Ordinary people don't want to follow the traditions and rituals that many religions place on its members. If I don't know what religion someone is, I often unknowingly place them under the 'spiritual but not religious' category. People who are religious and spiritual usually flaunt their religion. This happens many times in the United States with Christians. While I was in college there was a Christian group that asked participates what they thought about God. And then there's the not religious or spiritual category, which incorporates many atheists and agnostics.
I, myself try to be religious, but often fail. I'm not spiritual at all - I don't even believe in dualism. Things like The Sunday Assembly interest me, but there isn't one of them near my area. Unitarianism has been the fit for people who are both religious but not spiritual, and spiritual but not religious, due to their humanistic values and acceptance of other faiths.
I see a large difference between the two. Religious but not spiritual can refer to Unitarianism, Religion of Humanity, and certain sects of Satanism. The spiritual but not religious tend to reject mainstream religion and focus their efforts internally. To people that are spiritual but not religious, they often see religion as having to conform to something that doesn't suit what they are. I'm religious but not spiritual because I happen to agree with many of the ethics and rituals of religion, but I'm appalled by most, if not all, beliefs of most religions.
If I had to guess, I would say that, in the United States, 60% are religious and spiritual, 20% are spiritual but not religious, 15% are not religious nor spiritual, and 5% is religious but not spiritual. I am in the minority, I do realize that. Many people considered Communism to be a secular religion, something I do not agree with. There is a large difference between religious and spiritual. Religion is a shared activity that doesn't need to be spiritual, and spirituality is something internal that doesn't need to be shared with others.