Website Security Checks (CAPTCHA) really need to improve

I forgot my password in my LinkedIn and I'm trying to retrieve it. The security checks CAPTCHA words are not readable, c'mon two words to type is ok as long as I can read it. Here's a sample captured "security checks".

1st images:

These security checks help us prevent unauthorized access to your account.

Type the characters shown in the image above (not case sensitive).

I don't know about you, but I can't read this message so I clicked refresh, and got this new CAPTCHA words.

2nd refresh.

These security checks help us prevent unauthorized access to your account.

Type the characters shown in the image above (not case sensitive).

A little better compared to the previous CAPTCHA security, but still not able to answer the second word. Maybe I read it wrong. So I refresh again hoping to see a better words for security check.

3rd refresh:

These security checks help us prevent unauthorized access to your account.

Type the characters shown in the image above (not case sensitive).

Maybe, not my lucky day to get an easy two words security codes (CAPTCHA), so I gave up and leave the website.

How many visitors do you think have decided to leave after frustration of reading the security checks (CAPTCHA)? I have no statistic, or any reference to support this story, but I'm sure I am one of them.