Ok, now I understand. I did not require the use of the '%' character for the code I mentioned. To use the '%' the way you are referring, Pallav, yes that is how I would need to use it. However, the '%' character in the code I provided above is used to encode the '&' character where by '&' --> %26.
This allowed me to use the above method to put HTML in my trendlines using the dataXML method and not the dataURL method.