These two charts show the age distribution of the men who are either part of an active relationship or are seeking to begin one. The All Men chart shows both groups of men, of whom there are 212. The mean age for these men is 44.6 years, with a median age of 44 and a mode age of 53 (mode is the one with the highest frequency). Each bar represents one year, and the height is the number of men of that age.
The second chart shows the age distribution of men involved in a relationship, of whom there are 189 with a mean age of 45.2 years, a median age of 46, and a mode age of 53. Relationship is not precisely defined, it can mean married, living together pre- or post-K1 visa in the US or elsewhere, or just a serious commitment of some type. (In other words, the men who responded said they were in a relationship.)
Note that both of these distributions seem to roughly approximate the normal distribution curve (the bell-shaped line in the background). The second graph showing men with partners is a bit more weighted to the older/right side of the curve but not too much.
For all the histograms I have included what the normal distribution curve looks like for the sample. This is also called the bell curve because of its characteristic shape. This so-called normal curve shows what the population distribution would look like if this sample were randomly drawn from the population. There is nothing magical about a normal curve, it merely shows the natural distribution of many observations made in nature. For example, men's and women's height both are distributed normally. If the average man's height is 5' 10", the center peak of the curve will be at 5' 10", and the curve will slope downwards on both sides as there are fewer and fewer men shorter or taller than the average.