Recovery time.

<p>The estimation of recovery time <i>q</i>(<i>y</i>) is calculated as <i>q</i>(<i>y</i>) = <i>y</i>′ − <i>y</i>, where <i>y</i> is the first year when the high ratio <i>r</i><sub>high</sub>(<i>y</i>) falls below 90% of the baseline. Then <i>y</i>′ is the earliest subsequent year when the high ratio <i>r</i><sub>high</sub>(<i>y</i>′) returns to or exceeds 90% of the baseline.</p> <p>(PDF)</p>