Gravity falls off as 1/r^2 where r is your distance from the centre. The earth's radius is about 3960 miles. Adding 23 to that doesn't make much difference. The fraction is 3960^2/(3960+23)^2 = 0.988, i.e. about 1% weaker than on the surface.
@moth started
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Gravity falls off as 1/r^2 where r is your distance from the centre. The earth's radius is about 3960 miles. Adding 23 to that doesn't make much difference. The fraction is 3960^2/(3960+23)^2 = 0.988, i.e. about 1% weaker than on the surface.