Question: what are the nutritional fact in air-popped without butter or salt?
About the article "Popcorn", section "Nutritional value".

Candidate passages:
Although small quantities can be popped in a stove-top kettle or pot in a home kitchen, commercial sale of freshly popped popcorn employs specially designed popcorn machines, which were invented in Chicago, Illinois, by Charles Cretors in 1885.
Cretors successfully introduced his invention at the Columbian Exposition in 1893.
At this same world's fair, F.W.
Rueckheim introduced a molasses-flavored "Candied Popcorn", the first caramel corn; his brother, Louis, slightly altered the recipe and introduced it as Cracker Jack popcorn in 1896.
Cretors' invention introduced the first patented steam-driven popcorn machine that popped corn in oil.
Previously, vendors popped corn by holding a wire basket over an open flame.
At best, the result was a hot, dry, unevenly cooked snack.
Cretors' machine popped corn in a mixture of one-third clarified butter, two-thirds lard, and salt.
This mixture could withstand the temperature needed to pop corn and it produced little smoke.
A fire under a boiler created steam that drove a small engine; that engine drove the gears, shaft, and agitator that stirred the corn and powered a small automated clown puppet-like figure, "the Toasty Roasty Man", an attention attracting amusement intended to drum up business.
A wire connected to the top of the cooking pan allowed the operator to disengage the drive mechanism, lift the cover, and dump popped corn into the storage bin beneath.
Exhaust from the steam engine was piped to a hollow pan below the corn storage bin and kept freshly popped corn uniformly warm for the first time.
Excess steam was also used to operate a small, shrill whistle to further attract attention.
A very different method of popcorn-making can still be seen on the streets of some Chinese cities today.
The un-popped corn kernels are poured into a large cast-iron canister — sometimes called a 'popcorn hammer' — that is then sealed with a heavy lid and slowly turned over a curbside fire in rotisserie fashion.
When a pressure gauge on the canister reaches a certain level, the canister is removed from the fire, a large canvas sack is put over the lid and the seal is released.
With a huge boom, all of the popcorn explodes at once and is poured into the sack.
This method is believed to have been developed during the Song dynasty originally for puffing rice.
Individual consumers can also buy and use specialized popping appliances that typically generate no more than a gallon of popped corn per batch.
Some of these appliances also accept a small volume of oil or melted butter to assist thermal transfer from a stationary heating element, but others are "air poppers" which rapidly circulate heated air up through the interior, keeping the un-popped kernels in motion to avoid burning and then blowing the popped kernels out through the chute.
The majority of popcorn sold for home consumption is now packaged in a microwave popcorn bag for use in a microwave oven. 
A nut butter is a spreadable foodstuff made by crushing nuts.
The result has a high fat content and can be spread like true butter, but is otherwise unrelated.
Nut butters include:  Almond butter  Cashew butter  Hazelnut butter  Macadamia nut butter  Peanut butter  Pecan butter  Pistachio butter  Walnut butter The almond, cashew, macadamia, peanut, pecan, pistachio and walnut are not true nuts in a botanical sense.
However, because they are considered nuts in a culinary sense, their crushed spreads are called nut butters.
Similar spreads can also be made from seeds not considered nuts in a culinary sense:  Pumpkin seed butter  Sesame seed butter (usually called tahini)  Soybean butter - generally called "soynut butter" and made from soynuts (roasted soybeans)  Sunflower seed butter Nut and seed butters are rich in protein, fiber, and essential fatty acids and can be used to replace butter or margarine on bread or toast.
The following table gives some approximate nutritional properties of a selection of nut and seed butters.
It is important to note that many products contain additional oils or other ingredients that may alter the nut butter's nutritional content. 
Due to the prevalence of peanut allergies, many schools are offering peanut-free menu options or implementing entirely nut-free policies.
Sunflower butter can provide an alternative in schools where peanut butter and other nuts have been banned.
However, a small number of people with peanut allergies may also be allergic to sunflower seed butter.
According to one study a person with a known peanut allergy suffered an acute reaction to a "nut-free" butter containing sunflower seeds.
From a nutritional perspective, sunflower butter contains almost four times as much vitamin E as peanut butter, and about twice as much iron, magnesium, phosphorus and zinc.
Peanut butter contains higher levels of protein and slightly less sugar and fat. 
Normal butter softens to a spreadable consistency around 15 °C (60 °F), well above refrigerator temperatures.
The "butter compartment" found in many refrigerators may be one of the warmer sections inside, but it still leaves butter quite hard.
Until recently, many refrigerators sold in New Zealand featured a "butter conditioner", a compartment kept warmer than the rest of the refrigerator—but still cooler than room temperature—with a small heater.
Keeping butter tightly wrapped delays rancidity, which is hastened by exposure to light or air, and also helps prevent it from picking up other odors.
Wrapped butter has a shelf life of several months at refrigerator temperatures.
"French butter dishes" or "Acadian butter dishes" involve a lid with a long interior lip, which sits in a container holding a small amount of water.
Usually the dish holds just enough water to submerge the interior lip when the dish is closed.
Butter is packed into the lid.
The water acts as a seal to keep the butter fresh, and also keeps the butter from overheating in hot temperatures.
This allows butter to be safely stored on the countertop for several days without spoilage.
Once butter is softened, spices, herbs, or other flavoring agents can be mixed into it, producing what is called a "compound butter" or "composite butter" (sometimes also called "composed butter").
Compound butters can be used as spreads, or cooled, sliced, and placed onto hot food to melt into a sauce.
Sweetened compound butters can be served with desserts; such hard sauces are often flavored with spirits.
Melted butter plays an important role in the preparation of sauces, most obviously in French cuisine.
"Beurre noisette" (hazelnut butter) and "Beurre noir" (black butter) are sauces of melted butter cooked until the milk solids and sugars have turned golden or dark brown; they are often finished with an addition of vinegar or lemon juice.
Hollandaise and béarnaise sauces are emulsions of egg yolk and melted butter; they are in essence mayonnaises made with butter instead of oil.
Hollandaise and béarnaise sauces are stabilized with the powerful emulsifiers in the egg yolks, but butter itself contains enough emulsifiers—mostly remnants of the fat globule membranes—to form a stable emulsion on its own.
"Beurre blanc" (white butter) is made by whisking butter into reduced vinegar or wine, forming an emulsion with the texture of thick cream.
"Beurre monté" (prepared butter) is melted but still emulsified butter; it lends its name to the practice of "mounting" a sauce with butter: whisking cold butter into any water-based sauce at the end of cooking, giving the sauce a thicker body and a glossy shine—as well as a buttery taste.
In Poland, the butter lamb ("Baranek wielkanocny") is a traditional addition to the Easter Meal for many Polish Catholics.
Butter is shaped into a lamb either by hand or in a lamb-shaped mould.
Butter is also used to make edible decorations to garnish other dishes.
Butter is used for sautéing and frying, although its milk solids brown and burn above 150 °C (302 °F)—a rather low temperature for most applications.
The smoke point of butterfat is around 200 °C (400 °F), so clarified butter or ghee is better suited to frying.
Ghee has always been a common frying medium in India, where many avoid other animal fats for cultural or religious reasons.
Butter fills several roles in baking, where it is used in a similar manner as other solid fats like lard, suet, or shortening, but has a flavor that may better complement sweet baked goods.
Many cookie doughs and some cake batters are leavened, at least in part, by creaming butter and sugar together, which introduces air bubbles into the butter.
The tiny bubbles locked within the butter expand in the heat of baking and aerate the cookie or cake.
Some cookies like shortbread may have no other source of moisture but the water in the butter.
Pastries like pie dough incorporate pieces of solid fat into the dough, which become flat layers of fat when the dough is rolled out.
During baking, the fat melts away, leaving a flaky texture.
Butter, because of its flavor, is a common choice for the fat in such a dough, but it can be more difficult to work with than shortening because of its low melting point.
Pastry makers often chill all their ingredients and utensils while working with a butter dough. 
Butter churns have varied over time as technology and materials have changed.
Butter was first made by placing the cream in a container made from animal material and shaking until the milk has broken down into butter.
Later wood, glass, ceramic or metal containers were used.
The first butter churns used a wooden container and a plunger to agitate the cream until butter formed.
Later butter churns used a container made from wood, ceramics or galvanized (zinc coated) iron that contained paddles.
The hand-turned paddles were moved through the cream quickly, breaking the cream up by mixing it with air.
This allows the butter to be made faster than by simply agitating the cream.
Centrifugal cream separators allow the properties of centrifuge to be applied to butter making.
Instead of having spinning paddles, the paddles are fixed and the container spins.
This allows better separation of the butter from the buttermilk and water.
With electric mixers and food processors commonly available in most household kitchens, people can make butter in their own homes without a large churn.
These small appliances are used to mix the cream until it is close to forming solid butter.
This mixture is then mixed by hand to remove the buttermilk and water.