PDF export file size

Hello,

For some reason, all my exported PDF file sizes are huge. May i know the ways to optimize the file size. 

Here is the pen table details we are using.

! PROe DEFAULTS
! COLOR_NAME VISIBLE COLOR
! letter_color yellow
! highlite_color red
! drawing_color(geometry) white (pen1)
! background_color dark blue
! half_tone_color gray
! edge_highlite_color blue
! dimmed_color gray
! magenta magenta
! section_color cyan
!
!pen 1 Geometry, curves, volume
!pen 2 Letter
!pen 3 Hidden
!pen 4 Highlight
!pen 5 Sheetmetal
!pen 6 Section
!pen 7 Dimmed Menu
!pen 8 Edge High
!
!
! current settings for Pro/E drawings
pen 1 color 0.0 0.0 0.0; thickness 0.007 cm
pen 2 color 0.0 0.0 0.0; thickness 0.007 cm
pen 3 color 0.0 0.0 0.0; thickness 0.010 cm
pen 4 thickness 0.10 cm;color 0 0 0;SYSTEM_SELECTED_COLOR
pen 5 color 0.0 0.0 0.0; thickness 0.010 cm
pen 6 color 0.0 0.0 0.0; thickness 0.010 cm
pen 7 color 0.0 1.0 0.0; thickness 0.007 cm
pen 8 color 0.0 0.0 0.0; thickness 0.030 cm