The longitudinal section of a runway provides the following data:

$$\begin{array}{|lc|cI|}\hline &\textbf{End-to-end runway \textbf{(m)}} & \textbf{Gradient (\%)} \\ \hline &\text{0 to 300} & \text{+1.2} \\ \hline &\text{300 to 600} & \text{-0.7}\\ \hline &\text{600 to 1100} & \text{+0.6} \\ \hline &\text{1100 to 1400} & \text{-0.8} \\ \hline &\text{1400 to 1700} & \text{-1.0} \\ \hline \end{array}$$

The effective gradient of the runway (in $\%$, $\textit{round off to two decimal places}$) is ________________