Looking on the internet deeply has found these results:

I don't care. is the most popular phrase on the web.

I do not care. 1556,000 results on the web	I don't care. 174,700,000 results on the web More popular!
Some examples and use cases from the internet:	Some examples and use cases from the internet:
quite the contrary! Just don't ask me to indulge your narcissism. Jonathan ... I Do Not Care for the Winter Sun (Blackbird Blackbird Remix). Dream Jan 25, 2015 ... I do not care about your baby. It's not that I hate your little sprog Hop Blackbird Beach House dream ... Create a SoundCloud account. Sign in. Beach House The Fear of Missing Out: I Do Not Care About Bloodborne. By Maddy Myers. April 13, 2015 \| 11:00am. Share Tweet Share. Share Tweet. The Fear of Missing ... ... I do declare · I do Ishq Only Tumse · I Do Not Care · I Do Not Know · I Do Not Think So · I Do What I Can · I Do What I Want · I Don't Believe It · I don't believe it!	It doesn't look like this phrase is very popular! The search could not find any examples on the internet.

I do not care.

1556,000 results on the web

I don't care.

174,700,000 results on the web

More popular!

quite the contrary! Just don't ask me to indulge your narcissism. Jonathan ...
I Do Not Care for the Winter Sun (Blackbird Blackbird Remix). Dream
Jan 25, 2015 ... I do not care about your baby. It's not that I hate your little sprog
Hop Blackbird Beach House dream ...
Create a SoundCloud account. Sign in. Beach House
The Fear of Missing Out: I Do Not Care About Bloodborne. By Maddy Myers. April 13, 2015 | 11:00am. Share Tweet Share. Share Tweet. The Fear of Missing ...
... I do declare · I do Ishq Only Tumse · I Do Not Care · I Do Not Know · I Do Not Think So · I Do What I Can · I Do What I Want · I Don't Believe It · I don't believe it!

It doesn't look like this phrase is very popular! The search could not find any examples on the internet.