extract numerical values from DataFrame string object

I have a DataFrame object of dtype string. A typical row looks like below:

'\n\n              Dividend Indicated Gross Yield\n          \n\n              1.50%\n          \n'

I am trying to extract only the numerical data from the above string. for example, my desired output should be 1.50.

The other thing to keep in mind is that each row will have different length of numericals and some may include a negative sign too.

I have tried some recommendations involving .rstrip(), regex, convert_objects but they do not work as intended. Any help appreciated.

Copyright Notice：Content Author:「Siraj S.」，Reproduced under the CC 4.0 BY-SA copyright license with a link to the original source and this disclaimer.
Link to original article：https://stackoverflow.com/questions/30769519/extract-numerical-values-from-dataframe-string-object