      SUBROUTINE BOXFLT (NN,X,K,II)
C 
C     COMPUTES AVERAGES OF SERIES X IN NON-OVERLAPPING BLOCKS OF K. 
C     II IS THE NUMBER OF POINTS IN THE AVERAGED SERIES 
C 
      DIMENSION X(1)
      FK = K
      II = NN 
      IF (K.LE.1) RETURN
      NL=NN/K 
      NL=NL*K 
      II = 0
      DO 30 I=1,NL,K
      II = II+1 
      SUM = X(I)
      DO 20 J=2,K 
20    SUM = SUM + X(I+J-1)
30    X(II) = SUM/FK
      RETURN
      END 
