1840, Germans represented 21.4% of all European immigrants entering the USA; 32.2% in the following two decades; and at the end of the 19th century they were the largest immigrant group (21.9%) in the US. German immigration to Brazil was small compared to the numbers who went to the United States, and also compared to immigration of other nationalities, such as Portuguese, Italians and Spaniards, who together made up over 80% of the immigrants to Brazil during the period of greatest immigration by Europeans. Germans appeared in fourth place among immigrants to Brazil, but dropped to fifth place when Japanese immigration increased after 1908. Even though the immigration of Germans to Brazil was small, it had a notable impact on the ethnic composition of the country, particularly of the Southern Brazilian population. Different factors led to this large influence. First of all, German immigration to Brazil is an old phenomenon which started as early as 1824, many decades before the beginning of the immigration of other European ethnic groups to Brazil. For example, the first significant groups of Italians to immigrate to Brazil only arrived in 1875, many decades after the arrival of the first Germans. When the settlement of other Europeans in Brazil began, the Germans had already been living there for many generations. Another factor was the high birth rates among German Brazilians. Research has found that between 1826 and 1828 a first-generation German Brazilian woman had an average of 8.5 children, and the second generation had an average of 10.4 children per woman. The book The Monroe Doctrine by T B Edgington said: "The natural increase of the German population in southern Brazil is marvelous. As a rule they rear from ten to fifteen children in each family. Blumenau, a colony which was settled by the Germans over fifty years ago, more than doubles itself every ten years. Southern Brazil is now called 'Greater Germany', and the Germans exercise there a commercial and financial supremacy." Even though the population of German descent makes up a small minority in Brazil, they represent a very large percentage of the population of the South. Jean Roche estimated that people of German descent made up 13.3% of the population in Rio Grande do Sul in 1890, and that they had increased to 21.6% of the population in 1950. By 1920, the vast majority of the population of German descent was Brazilian-born.