The graph below shows Washington’s winning percentage after each game this season:

The season began with a home loss to Miami, the start of a loss-win-loss-win-loss pattern that defined the team’s first five games. The sixth game was a loss to the Jets, followed by a win-loss-win-loss-win-loss pattern that brought the team’s record to 5-7. Finally, after three straight wins, Washington now has a winning record at 8-7. In the process, the team clinched the disappointing NFC East: that’s because the Eagles and Cowboys will finish with losing records, while the Giants would lose a tiebreaker (based on NFC record) to Washington at 8-8.

The last time Washington made the playoffs, it was with a quarterback drafted in 2012 and following a slow start, too: that year, the team began 3-6 but finished 10-6. There are more than a few similarities between those two teams, particularly at quarterback. Over his last 9 games, Kirk Cousins has completed 72% of his passes for 2,570 yards (8.57 Y/A), with 20 TDs and 3 INTs, while also rushing for four touchdowns. In RG3’s last 10 games of his rookie season, he threw for 2,039 yards (8.0 Y/A) with 16 TDs and 4 INTs, while also rushing for 574 yards with three scores.

But what I’m more curious about today is something I’ll call average winning percentage. After game 1, Washington’s win percentage was 0.000; after a week two win, the team’s winning percentage was 0.500, which means its average winning percentage through two weeks was 0.250. A loss the next week dropped the team’s winning percentage to 0.333; that gave Washington an average winning percentage through three weeks of 0.278. The table below shows the team’s actual winning percentage and average winning percentage after each game this year:

Gm Opp W/L Win % Avg Win% 1 Miami Dolphins L 0.000 0.000 2 St. Louis Rams W 0.500 0.250 3 New York Giants L 0.333 0.278 4 Philadelphia Eagles W 0.500 0.333 5 Atlanta Falcons L 0.400 0.347 6 New York Jets L 0.333 0.344 7 Tampa Bay Buccaneers W 0.429 0.356 8 New England Patriots L 0.375 0.359 9 New Orleans Saints W 0.444 0.368 10 Carolina Panthers L 0.400 0.371 11 New York Giants W 0.455 0.379 12 Dallas Cowboys L 0.417 0.382 13 Chicago Bears W 0.462 0.388 14 Buffalo Bills W 0.500 0.396 15 Philadelphia Eagles W 0.533 0.405

A win in week 17 against Dallas will raise the average winning percentage for Washington in 2015 to 0.415; a loss will still raise it to 0.411, since an 8-8 record would be better than the average winning percentage of the team through 15 games. In the abstract, this may not mean much, but where does that compare to other playoff teams?

In 2012, Washington had an average winning percentage of 0.504; that’s below average for a 10-6 team, but obviously a bit better than this year’s team. The table below shows the 20 playoff teams with the worst average winning percentages in pro football history: as you can see, Washington’s 2015 team will slot in just outside of the top 10:

Rk Team Year Lg Record Avg Win% 1 Tampa Bay Buccaneers 1982 NFL 5-4 0.274 2 Buffalo Bills 1963 AFL 7-6-1 0.346 3 New Orleans Saints 1990 NFL 8-8 0.347 4 Detroit Lions 1995 NFL 10-6 0.354 5 San Diego Chargers 2008 NFL 8-8 0.366 6 San Diego Chargers 1992 NFL 11-5 0.384 7 Buffalo Bills 1948 AAFC 7-7 0.387 8 Cincinnati Bengals 1970 NFL 8-6 0.403 9 Pittsburgh Steelers 1989 NFL 9-7 0.407 10 Denver Broncos 2011 NFL 8-8 0.411 11 Buffalo Bills 1949 AAFC 5-5-2 0.413 12 New York Jets 1981 NFL 10-5-1 0.420 13 New England Patriots 1994 NFL 10-6 0.422 14 Arizona Cardinals 1998 NFL 9-7 0.426 15 Philadelphia Eagles 1990 NFL 10-6 0.435 16 Houston Oilers 1990 NFL 9-7 0.438 17 San Diego Chargers 2013 NFL 9-7 0.442 18 Minnesota Vikings 2008 NFL 10-6 0.442 19 Indianapolis Colts 1987 NFL 9-6 0.447 20 Jacksonville Jaguars 1996 NFL 9-7 0.449

The 1982 season was strike-shortened to just nine games and the league allowed 16 teams to make the playoffs; as a result, a Tampa Bay team that started 0-3 and 2-4 made it to the postseason, and the 9-game schedule didn’t provide enough of a runway for the team’s average winning percentage to improve.

In 1990, the Saints made the playoffs at 8-8, and held 0-2, 1-3, 2-5, 4-6, 5-7, and 6-8 records at various points. In 2008, the Chargers were 0-2, 2-3, 3-5, and 4-8, before going on a four-game winning streak to win the AFC West at 8-8. Three years later, the Tim Tebow Broncos were 1-4 and 2-5 before winning six straight games. That was followed by three straight losses, but the 8-8 record was enough to clinch the division.

Given the team’s average winning percentage, and its expected last-place finish in the division, that makes Washington one of the most unlikely playoff teams in recent memory. Washington fans sure like that.