In the western world, most people get far too less fibre in their food 

It is estimated that one should get at least every day 30 grams of fibre if not more

I will give a rough idea of how much fibre one eats every day by calculating certain foods.

A serving of fruits is considered to be at least one whole fruit such as an apple or a banana This would be equal to 2 grams of fibre

To get 2 grams of fibre from grains one needs to eat at least half a cup of cooked brown rice half a cup of whole grain pasta, one slice of whole grain bread or if you prefer to weigh then one ounce [that is  more of less30 gram] of uncooked  whole grain wheat, pasta brown rice etc is equal to 2 gram of fibre

A serving of vegetables which is also 2 gram of fibre is more or less 150 gram 

1/2 cup of legumes may contribute to 8 grams of fibre!!!

This is all a rough estimation and not all fruits or vegetables are equal of course and realize that whole grains and legumes are very important to get enough fibre.

The above is useful to get an idea of how much fibre one eats on an average per day

Serving is a typical American expression!

See also the video from Gr Greger