Percentage increase is 14.29%.
$\text{% increase} = \dfrac{ \color{red}{ \text{final value} } - \color{blue}{ \text{initial value} } }{ \color{blue}{ \text{initial value} } } \times 100$ | $$ \begin{aligned} \color{red}{ \text{final value} } &= 6.4 \\[1.5em] \color{blue}{ \text{initial value} } &= 5.6 \end{aligned} $$ |
$\text{% increase} = \dfrac{ \color{red}{ 6.4 } - \color{blue}{ 5.6 } }{ \color{blue}{ 5.6 } } \times 100 $ | |
$\text{% increase} = 0.1429 \times 100 $ | |
$\text{% increase} = 14.29 \% $ |