This works (assuming the column separator's a space):
$string = "java 14.59%"
($string -split " ")[1]
If there are multiple spaces (or tabs or other 'whitespace' characters) separating the columns, then this will work:
$string -replace "^.+?\s+(.+)$",'$1'
Or even this (if it's always spaces as separators):
$string.split(" ",[System.StringSplitOptions]::RemoveEmptyEntries)[1]