How can rotated table headers be left justified?
Currently have this:
\documentclass[a4paper,8pt,twocolumn]{extarticle}
\usepackage{graphicx,multirow}
\begin{document}
\begin{tabular}{l r c c c c c c c}
\textbf{bla1}&\multirow{2}{*}{\textbf{bla2}}&\multirow{2}{*}{\textbf{\rotatebox{90}{bla3}}}&\multirow{2}{*}{\textbf{\rotatebox{90}{blablablablablabalbal4}}}\\
\textbf{\textit{bla5}}\\
\end{tabular}
\end{document}