Here is a comparison of beers, wines and spirits volume of pure alcohol basted on what is known
as a "standard serving" of each. Look at it like this a 12 oz. cocktail with 1.5 oz. of 80 proof spirits has about 0.6 oz. of pure alcohol, and a 12 oz. beer which is rated at 5% (10 proof) alcohol also contains 0.6 oz. of pure alcohol. Below is a chart that shows how much alcohol there is in a "standard serving" of alcoholic beverages.
12 fl. oz. of regular beer = 5% alcohol = 0.6 fl. oz. Pure Alcohol
12 fl. oz. of malt liquor = 7% alcohol = 0.7 fl. oz. Pure Alcohol
5 fl oz of table wine = 12% alcohol = 0.6 fl. oz. Pure Alcohol
3 fl oz of fortified wine = 19% alcohol = 0.6 fl oz. Pure Alcohol
2.5 fl oz of cordial, liqueur, or aperitif = 24% Alcohol = 0.6 fl. oz. Pure Alcohol
1.5 fl oz of brandy or cognac = 40% Alcohol = 0.6 fl. oz. Pure Alcohol
0.95 fl. oz. shot of 151 proof spirit = 75.5% Alcohol = 0.7 fl. oz. Pure Alcohol
As you can see from the chart, if you are consuming alcoholic beverages of any kind, you are taking in a very equal amount of pure alcohol from any category. Don't fool yourself into trouble by believing that beer has less alcohol that 151 proof spirits, because standard servings of any of these is really about the same amount of pure alcohol content.