According to Bureau of Labor Statistics, 69% of women cook in the household. Problem with the data is that it doesn't account for for what percentage of that 69% is made up of women married to men whom also cook.
How it does not account exactly? The data is right there:
http://www.bls.gov/news.release/atus.nr0.htm
http://www.bls.gov/news.release/atus.t01.htm
Household Activities in 2014
--On an average day, 83 percent of women and 65 percent of men spent some
time doing household activities such as housework, cooking, lawn care, or
financial and other household management. (See table 1.)
--On the days they did household activities, women spent an average of 2.6
hours on such activities, while men spent 2.1 hours. (See table 1.)
--On an average day, 20 percent of men did housework--such as cleaning or
laundry--compared with 49 percent of women. Forty-three percent of men did
food preparation or cleanup, compared with 69 percent of women. Men were
slightly more likely to engage in lawn and garden care than were women--11
percent compared with 8 percent. (See table 1.)
--From 2003 to 2014, the share of men doing food preparation and cleanup on
an average day increased from 35 percent to 43 percent. Over this same period,
the share of women doing housework on an average day decreased from 54 percent
to 49 percent. The average time per day women spent doing housework declined by 9
minutes, from 58 minutes in 2003 to 49 minutes in 2014. (See table 1.)
This is not exactly what you asked for(what percentage of women that cook are married to men that also cook), but I don't see why that specific piece of data is especially important. On average, 43% of men do cooking or cleanup, against 69% of women. My statistic skills are not good enough to know if we can calculate what you asked for based on this, but again, I think the 43% vs 69% paints a pretty clear picture already.
Also, if you watch the table, you'll see that indeed men spend more time doing lawn&garden care than women(0.25h vs 0.12h). Problem is, when summing up "Household Activities", of which lawn&garden care are part of, women spend 2.14h against 1.38h of men. 0.82h for food preparation and cleanup, against 0.34h for men. You'll see that "lawn and garden care" takes only 0.25h(average hours per day) and the average percent engaged in this activity per day is ~10%, against food preperation and cleanup which takes 0.82h(average hours per day) and average percent engaged in this activity per day is 56.3%.
Which lines up with what I said: Cooking and cleaning is for every day, things like lawn care are much less often needed. They might even take longer when they're being done(I believe this is what "Average hours per day for persons that engaged in this activity" is for, which shows 2.37h for lawn care, longer than any other household activity), but they're not executed nearly as often("Average percent engaged in this activity per day", 10% for lawn care, lower than any other household activity). It's actually pretty intersting to see how things interact between the 1st and 3rd table(which is average hours per day against average hours per day for persons actually enganged in the activity). Cooking does not change much for women(1.19h when engaged, 0.89h on average), but lawn care for men, it changes drastically(2.37h when engaged, but only 0.25h on average).