*In 1996, Perot received 8.4% of the vote.
As the chart above indicates, Anne Arundel County has voted for the Republican presidential candidate in every year since (at least) 1972 (summaries back to 1960 are available here). The margins have fluctuated, but until 2008 had been 7 points at a minimum in 1996 and as much as 28 points in 1988. Thus, even when Ross Perot was on the ballot, Republican candidates mantained a significant advantage in the county.
The last two presidential elections have seen a significant decrease in that margin: 1.8% in 2008 and just 0.9% in 2012. This year also marked the first time that (notwithstanding a strong third party candidate) the Republican candidate did not gain at least 50% of the county's voters.
Turnout in the county was down--69% across the county (which was the same turnout as statewide) compared to 79% in the county in 2008 (78% statewide).
UPDATE: The 69% turnout figure that I cited does *not* include absentee or provisional ballots. In 2008, Anne Arundel County had 17,540 absentee ballots and 3,942 accepted provisional ballots. These ballots represented 8.2% of the total turnout; turnout without them would have been 72.9% without them. Extrapolating similar absentee and provisional ballots for 2012, turnout projects to be about 75-76%.