NRCS changed the structure of the website for basin plots, so the link doesn't work anymore. Try THIS LINK
and select the type of plot you want. The top selection is the statewide graph with all the basin % of averages. It's a pdf now, so no point-n-click link to the basin plot from the state graph. You have to select that from the list on the above link. (Second line, then select the specific basin you want.) Hope that helps you!