A lot.
Christians have often claimed that many atheists are actually (deep down...) believers in God; but I suggest the opposite: that here-and-now the problem is that most self-described Christians are really atheists.
How do I know? By application of an insight from Rudolf Steiner, which is that when someone denies the God - that is, denies a Divine Principle in the world - then there is an actual physical defect, sickness, and flaw in that person.
The atheist denies something that he should be able to feel, and feel naturally, simply by means of his actual bodily constitution.
And when someone denies that which gives him a healthy bodily feeling, namely that the world is pervaded by Divinity, then he is a sick man, sick in body.
By this test, as well as the large proportion of explicit atheists, many or most professed Christians are also atheists - and this is an objective, observable fact which is seen in their behaviour: that is, they behave as sufferers from the same physical illness which can be seen in atheists.
The effect of this illness is profound - indeed it accounts for the dominant and striking distinctive features of modernity... that blank, defocused, ungrounded, alienated affect which almost everybody displays (whether covered by a superficial striving, or not).
...This is the behaviour of someone who believes that reality has no meaning, but is merely a combination of change and rigid determinism; and therefore the behaviour of someone who inhabits a world in which only business of an individual is to maintain some kind of emotional adjustment to a senseless situation over the short-term.
This behaviour, characteristic of deep atheism, is the norm; so much the norm, indeed, that little else can be found anywhere - whatever convictions, or lack of conviction, an individual may profess. Just look-around, just speak to people with this in-mind...
By this test I discern that we inhabit a world of atheists, almost entirely.
Our problems go much deeper than we commonly recognise; and 'conversion' to normal Christianity believed in the normal way is grossly inadequate. To profess a belief in God is ineffectual when what is necessary is a new world-view, rebuilt from the ground of fundamental convictions and attitudes, upwards.