Double Trouble

So, I was browsing the SSA database, wishing that the 2012 stats were out (three more weeks?!? GAH.), and came across the most common twin names. I know I've seen this before, but I never really looked too hard. I mean, statistically, the most common names for kids overall are still going to be pretty common for twinsies, too, right? Partially.
What I failed to consider is the common proclivity towards "matchy" names. What seems to happen quite frequently is for one twin to get a popular name, and the other to get an uncommon "match". Names that are quite uncommon overall are disproportionately more common for a twin.
Now, the data isn't perfect, of course--it only shows most common twinsets.  So, a name like Kaylee, which has dozens of spelling in use, doesn't rank highly at all. Also, a name could theoretically be in use frequently, but not paired with any one name particularly often. It wouldn't show up in these rankings either.
So, with those limitations in mind, here're some interesting stats:

The most common twin pairs are: Olivia & Sophia, Madison & Mason; Daniel & David.
However, if you break the pairs up:

G/G Names			B/G Names			B/B Names
Olivia	142		Mason	70		Jayden	120
Sophia	142		Madison	60		Logan	98
Emma	120		Ethan	49		Ethan	91
Isabella	91		Emma	44		Joshua	90
Ava	74		Isabella	39		Jacob	89
Abigail	60		Olivia	39		Isaiah	85
Madison	58		Abigail	38		Andrew	69
Ella	57		Jayden/Jaden	37		Alexander	67
Makenzie/Mackenzie	88		Jada/Jayda	36		Benjamin	67
Gabriella	48		Addison	26		Nathan	66
Faith	46		Aiden	25		Matthew	65
Makayla	40		Alexander	25		Daniel	58
Emily	34		Sophia	24		David	58
Hope	33		Emily	22		Jordan	53
Hailey/Haylee	31		Chloe	21		Noah	53
Heaven	29		Jacob	20		Elijah	52
Nevaeh	29		Ava	19		Michael	52
Mia	26		Michael	19		Isaac	47
Addison	24		Andrew	18		Nicholas	46
Elizabeth	22		Owen	18		Aiden/Ayden	42
Hannah	18		Zoey	18		Evan	39
Avery	15		Zachary	17		Lucas	39
Arianna	14		Isaiah	14		Jeremiah	33
Brianna	14		Jackson	14		Anthony	31
London	14		Ella	12		Jaylen	26
Paris	14		Taylor (g)	12		Mason	26
Grace	13		Tyler	12		Justin	25
Kaylee	13		Landon	11		Kayden	25
Samantha	13		London	11		Landon	25
Anna	12		Morgan	11		William	24
Chloe	12		Oliver	11		Caleb	23
Evelyn	12		Benjamin	9		James	23
Reagan	12		John	9		John	23
Riley	12		Mackenzie	9		Josiah	21
Zoey	12		Matthew	9		Luke	21
Sarah	11		Michelle	9		Chance	20
Jayla	10		Adrian	8		Chase	20
Katherine	10		Adriana	8		Hayden	20
Kayla	10		Charlotte	8		Hunter	20
Morgan	10		Elizabeth	8		Gabriel	19
Mya	10		Henry	8		Joseph	19
Natalie	10		Isaac	8		Samuel	17
Nicole	10		Jayla	8		Christian	16
Serenity	10		Samuel	8		Christopher	16
Trinity	10		William	8		Brandon	15
Autumn	9		Blake	7		Bryan	15
Sophie	9		Brooklyn	7		Liam	15
Summer	9		Caleb	7		Jason	13
Valentina	9		Colton	7		Maddox	13
Valeria	9		Connor	7		Garrett	12
			Jack	7		Gavin	12
			Jordan (b)	7		Henry	12
			Natalie	7		Jeremy	12
			Nathan	7		Jonah	12
			Robert	7
			Trinity	7
			Tristan	7
			Zane	7
			Austin	6

Most of the names aren't too surprising. Logan, however, is ranked either #20 or #26 (depending on whether you prefer the SSA ranking or the NameNerds rankings). Why is it so much more popular for twins? Because of its matchy-ness with other names--particularly Landon, Lucas, Luke, & Liam. Hope is down in the 200s, but it's commonly paired with Faith. Jayda/Jada is fairly uncommon as well, but is frequently paired with Jayden/Jaden & Jordan.

David & Daniel are the most common twinset for boys...but they only appear paired with each other! There are a few of these sets--Heaven & Nevaeh, London & Paris, Reagan & Riley, Jayla & Kayla, Summer & Autumn, Valentina & Valeria; Blake & Brooklyn, Taylor (g) & Tyler; Chance & Chase, Hayden & Hunter, Christian & Christopher. Unsurprisingly, "matchy" names are more common for g/g sets.
(It's a bit depressing, actually.)

I also find it interesting that of all the unisex names, only Jordan shows up as only male. Jordyn is a fairly popular name, so I'm at loss as to why it doesn't appear in twin-sets often.