The record books have been amongst the biggest winners in Doha this week.

The first three days saw three different athletes make history for their respective nations at the World Championships.

Monday set the ball rolling when Uganda's Halimah Nakaayi shocked the world by winning the 800m, the first time her country has won gold in the event. Tuesday night was Australia's turn for glory, as Kelsey-Lee Barber became her nation's first ever winner in the javelin at a world championships. And Wednesday,of course, was when Great Britain's golden girl Dina Asher-Smith raced to the 200m gold, the first time Team GB has a 200m women's winner at the world championships.

The incidence of a country's first medal, or gold medal, in an event at a world championships has not been uncommon this century. For the women, it has happened 189 times since 2001, but as of Thursday night, it had happened only 13 times in Doha.

So, why are these moments of history dwindling in their frequency? We take a look at the stats behind the facts.

The last 18 years - magical moments in overdrive

The 2001 World Championships in Edmonton saw 28 women from 21 countries make history by winning a medal, or gold medal, in an event that their nation had never won in before.

Russia dominated, with four different athletes winning medals in events like the heptathlon and the marathon, in which Russia had never won before.

As can be seen by the chart below, history of this kind is made at least 16 times every championships and countries like the Bahamas and Poland have seen a number of their athletes win a medal for the first time in an event.

The world championships of four years ago saw Ethiopia, Germany, Cuba, the Netherlands and Belarus all with two athletes winning their country's first medal in an event.

Countries are finding their strength and sticking to it

A key explanation could be that countries are finding events in which their athletes perform best and then stick to it for future generations.

If we take the 100m, only once since 1993 has a country outside of the USA or Jamaica won the gold medal. In fact, between the period of 2005 and 2015, USA and Jamaica combined to win 14 of the 18 medals available in the women's 100m.

From the origin of the 10,000m in 1987 it seemed like China would go on to dominate for generations because of athletes like Zhong Huandi and Wang Xiuting, who combined for medals across three consecutive world championships.

But now, despite the Netherlands' Sifan Hassan winning this year, Ethiopia and Kenya sweep the board. An incredible 25 out of the last 30 medals in the 10,000m at the world championships have been taken by these two nations.

The last five long jump winners have been from the USA, and between 2007 and 2013, only athletes from New Zealand won the women's shot put at the world championships.

Let's hope that the last few days of action in Doha will create even more memorable moments for nations who are not expected to win, but as the statistics show, it is going to be increasingly difficult.