I think we all come from the one Source or God. Not too sure what the second part of your question is asking Vee - the sum total incarnations are obviously more than the current number of people incarnated on earth.

Before anyone can answer that, there are a few questions we need to answer definitively:

• What is a Soul?
• Did humans make up this concept, or is there evidence based on physical reality that we can back up this concept?
• If we can be certain souls are real, then what are the logistics of it?
• Is there a finite amount of souls or is there a soul generator?
• What are souls made of?
• How are they formed?
• How do they attach to a physical body?

And the Ultimate quest:

• Is this even knowable to us?

I don't think it is.

I would think there are an increasing number of souls than ever before. No clue where they come from but it appears we have the choice to increase or decrease that number which strikes me as odd. (i.e. - China's one child policy)

every effect has a cause,
and maybe we are too ignorant yet to understand some things about life.
it is said by some that life, as we know it, is the manifestation of spirit
as involuted from the prime mover into myriads of form on it way down into density of matter.
interesting concept, when one considers all variations are concreted of and from the same all/source,
as we still delude ourselves in separateness instead of diversity