ClearAll[TwinPrimeCount]
TwinPrimeCount[mx_] := Module[{pmax, min, max, total},
  pmax = PrimePi[mx];
  total = 0;
  Do[
   min = 10^6 i;
   min = Max[min, 1];
   max = 10^6 (i + 1);
   max = Min[max, pmax];
   total += Count[Differences[Prime[Range[min, max]]], 2]
   ,
   {i, 0, Ceiling[pmax/10^6]}
   ];
  total
 ]
Do[Print[{10^i, TwinPrimeCount[10^i]}], {i, 9}]