It should be "Second," and also,
"According to the National Assessment of Adult Literacy in the USA, the percent of illiterate persons over 14 in 1920 was 6%; in 1950, 3.2%; in 1979, 0.6%. "
if it matters. I can't find any other errors, can you?
The sentence, "According to the Huffinton Post, in the past 10 years, there has been no significant change in the literacy rate in the US. " is awkward, I suggest "According to the Huffinton Post, there has been no significant change in the literacy rate in the US in the past 10 years. "
to many times? :-)