Since 1987, Pew Research has asked this survey question: “As I read a list of some stories covered by news organizations this past week, please tell me if you happened to follow each news story very closely, fairly closely, not too closely, or not at all closely. News about candidates for the [relevant year's] presidential election. ...”
This chart, which updates one that political scientist Charles Franklin did for Pollster back in 2007, shows the share of Americans who said they were following news about presidential candidates "very closely" in election cycles from 1988 through 2016. The starting point varies, but in every case Pew asked the question at least 15 months ahead of the November election. In recent cycles, the question was asked 21 to 22 months out.
The share of Americans paying close attention to the race for the White House starts out low -- under 10 percent in 2004 and not much higher in most other years. 2008 is the only cycle in which more than 20 percent were really following the race early, but even in that cycle, attention waned a bit before it began climbing toward Election Day.
According to Scott Keeter, Pew's director of survey research, “The big reason for low levels of attention to the campaign at this point in the cycle is that most people just aren't that interested in politics. Combine that with a general sense that nothing going on right now matters very much for the actual outcome, and you can understand why so few people are following at this point.”
SEE PEW DATA HERE.