documentclass{article}
 usepackage[margin=0.5in,a4paper]{geometry}
 usepackage{caption}
 usepackage{capt-of}
 usepackage{longtable}
 usepackage{array, booktabs, makecell, multirow}
 renewcommandtheadfont{bfseriessmall}
 usepackage{arydshln}
 setlengthdashlinedash{0.2pt}
 setlengthdashlinegap{1.5pt}
 setlengtharrayrulewidth{0.3pt}
 usepackage{pdflscape}
 usepackage{afterpage}

 %Widows & Orphans & Penalties

 widowpenalty500
 clubpenalty500
 clubpenalty=9996
 exhyphenpenalty=50 %for line-breaking at an explicit hyphen
 brokenpenalty=4991
 predisplaypenalty=10000
 postdisplaypenalty=1549
 displaywidowpenalty=1602
 floatingpenalty = 20000
 usepackage{siunitx}

  begin{document}
  afterpage{clearpage}
  thispagestyle{empty}
  begin{landscape}
  begin{table*}[ht] centering
  begin{tabular}{ l*{6}{S[table-format=2.2]} } toprule
  label{tab:oaxaca}
  thead[b]{Terms of \ decomposition}  & multicolumn{3}{c}{2011-12} &
  multicolumn{3}{c}{2004-05} \
  cmidrule(lr){2-4}cmidrule(lr){5-7}cmidrule(lr){5-7}
  midrule
   & textbf{women ws} & textbf{male ws} & textbf{pooled ws} & textbf{women ws} & textbf{male ws} & textbf{pooled ws} \ hline
  \
  {Difference} & 0.39 & 0.39 & 0.39 & 0.48 & 0.48 & 0.48 \ hdashline
  {Explained} & -0.02 & 0.00 & -0.01 & 0.17 & 0.18 & 0.17 \ hdashline
  {Unexplained} & 0.41 & 0.39 & 0.40 & 0.31 & 0.30 & 0.31 \ hline
  {Percent unexplained} & 103.95 & 99.42 & 102.62 & 65.42 & 61.88 & 65.00 \
   bottomrule
   end{tabular}
   caption{Oaxaca Blinder Decomposition results}
   end{table}


  end{landscape}
  end{document}