A month ago, the Detroit Lions were trying to aim to be one of the top defenses in recent NFL history.

That pace has fallen off a little bit in several areas, but the Lions still have a lot to like with their top-ranked defense. As we did a month ago, here’s a look at where Detroit's defense stands in some categories, with some historical perspective.

Week 6 numbers in parentheses.

QBR

The number: 36.7 -- No. 2 in the NFL (23.5, No. 1)

What it means: The Lions have faced some of the league's better quarterbacks, including Drew Brees and Matt Ryan. This week, the Lions face Tom Brady, so this number could grow.

Historical comparison: The Dolphins and Lions are the only teams under 40 in defensive QBR, but that isn’t a major statistical breakthrough. Six teams were under a 40 QBR last season. Of those teams, though, only the Bills had a record below .500.

Yards per game

The number: 290.3 -- No. 1 in the NFL (270.7, No. 1)

What it means: It isn’t surprising there has been an uptick in yardage gained on the Lions, who are continuing to deal with injuries. But they are still the only team in the NFL allowing less than 300 yards per game.

Historical comparison: After six weeks, there were comparisons to the 2009 Jets defense. Right now, the Lions’ yardage is a bit less impressive. The Seahawks, at 273.6, were better last season. If this holds for Detroit, they would be the first team to lead the NFL in yards per game at 290 or worse since at least 2001. Typically, at least one NFL team hovers around 270 yards per game allowed.

Yards per play

The number: 4.82 -- No. 3 in the NFL (4.49, No. 1)

What it means: The uptick follows with the increase in yards per game and facing better offenses, which continues this week against New England. That Miami and Denver have both passed Detroit is an interesting marker to watch. The almost 0.4 yards per play doesn’t seem like much, but it adds up.

Historical comparison: It is below average among top defenses. Last season, Seattle was at 4.42 yards per play, for instance.

Rushing yards per game

The number: 68.8 -- No. 1 in the NFL (73.5, No. 2)

What it means: The Lions have been devastating against opposing backs and are the only team in the league holding teams under 70 yards rushing per game. They are one of two, along with Denver, at less than 75 yards a game.

Historical comparison: If the number holds, they’ll have the best run defense since 2010, when the Steelers held opponents to 62.75 yards per game. The Lions would be one of three teams since 2001 (the 2006 Vikings were the third team) to hold opponents under 70 yards rushing a game.

Yards per rush

The number: 3.03 -- No. 1 in the NFL (3.27, No. 4)

What it means: It goes with the yards per game, but teams have become mostly one-dimensional against the Lions, which helps the overall defense and defensive numbers. The Lions, right now, are 0.28 yards better per carry than any other team in the league.

Historical comparison: This would be the best number since those 2010 Steelers at 3.02 yards per carry. The 2006 Vikings set the benchmark at 2.83 yards allowed per carry and the 2007 Ravens allowed 2.84 yards a carry.

Passing yards per game

The number: 221.5 -- No. 5 in the NFL (197.17, No. 1)

What it means: With teams unable to run on Detroit, they’ve resorted to passing. Detroit also ran into a couple of prolific passing teams against New Orleans and Atlanta. More of the same this week against the Patriots.

Historical comparison: Not much here.

Sacks per attempt

The number: 7.4 percent -- No. 10 in the NFL (9.7, No. 1)

What it means: The Lions are still pressuring quarterbacks but have seen more experienced -- and more mobile -- quarterbacks of late. That’s helped knock those numbers down a bit. Don’t be surprised to see this number be higher by the season’s end.

Historical comparison: Again, none necessary.

First downs per game

The number: 18.6 -- No. 4 in the NFL (16.8, No. 1)

What it means: The Lions are good here, as they are one of six teams allowing less than 19 first downs a game. But the number doesn’t mean a ton considering the Jets, Redskins and Vikings join them in that company and are all below .500.

Historical comparison: Average among top defensive units.

Points allowed per game

The number: 15.6 -- No. 1 in the NFL (13.7, No. 1)

What it means: The Lions are the only team holding opponents under 17 points a game. That’s the major reason Detroit is 7-3 and should be in any game it plays the rest of the season. Of teams in the top five in points allowed per game, the Lions (point margin of plus-3.2) are the only team under plus-6 points per game.

Historical comparison: The numbers are a little higher than other top defenses of recent past, but by only a point or so, so they're in line there.