Question:
I need to know how to convert the ratio 66:1 to a percentage. I can not find an answer any where on-line when the second number is a 1. Thank you for your help.

Percentage questions can be subtile. When asked for a percentage it helps to ask "percentage OF WHAT?"

Suppose that you have 5 apples and I have 2 apples then the ratio of the number of apples I have to the number of apples you have is 2:5. That is I have two-fifths the number of apples that you have. As a percent, 2/5 is 40% so the number of apples I have is 40% of the number of apples that you have.

If you, however, you tell me that the ratio of the number of apples I have to the number that you have is 2:5 and ask for the percent that I have, you may be asking "What percentage of the apples do you have?" In this case I have 2 of the 7 apples so I have  ²/₇x100 = 28.6% of the apples.

If that ratio is a:b then in the first interpretation, a is  ^a/_b x 100% of b and in the second interpretation, a is  ^a/_a + b x 100% of a + b.

For your example where the ratio is 66:1, 66 is 6600% of 1 (that is I have 66 times as many apples as you have) and 66 is  ⁶⁶/₆₇ x 100 = 98.5% of 67 (that is I have 98.5% of the apples).