ad lib vs throw something together

ad lib

adj

Extemporaneous, impromptu.

adv

Extemporaneously.
At will.
To whatever extent.
At pleasure.

verb

To perform without preparation.
To perform without script.
To perform extemporaneously.

throw something together

How often have the words ad lib and throw something together occurred in a corpus of books? (source: Google Ngram Viewer )