Data collected from various sources indicate that in any given year, 2000 people should be struck by lightning, while approximately 30% of those struck will die.
(A) in any given year, 2000 people should be struck by lightning
(B) 2000 people should be struck by lightning in any given year
(C) lightning will strike human beings 2000 times per year
(D) each year, 2000 people will be struck by lightning
(E) each year, lightning should strike 2000 times

Source: Kaplan
Correct Answer : D
I found this question similar to OG11 SC#124.
If we use correct answer D, then sentence would become as below:
Data collected from various sources indicate that each year,[COMMA] 2000 people will be struck by lightning, while approximately 30% of those struck will die.

I want to know the significance of COMMA between 'year' and '2000'.
While solving this question I stuck between C and D, and in option D, '2000 people will be struck by lightning' was looking like a modifier so I selected option C over D.
Ideally 'that' clause should have SV Pair but by using option D it seems there is no SV pair (if we have COMMA between 'year' and '2000').
Could any expert please explain this sentence structure?