The following article provides an analysis of International tourism data from 1995 to 2018.
The data is from the World Bank
International tourism - 2018 - Arrivals and Departures.
The below graph shows the top 10 countries by number of arrivals and departures in 2018.
Tourism outbound - International tourism, number of departures
International outbound tourists are the number of departures that people make from their country of usual residence to any other country for any purpose other than a remunerated activity in the country visited. The data on outbound tourists refer to the number of departures, not to the number of people traveling. Thus a person who makes several trips from a country during a given period is counted each time as a new departure.
Tourism inbound - International tourism, number of arrivals
International inbound tourists (overnight visitors) are the number of tourists who travel to a country other than that in which they have their usual residence, but outside their usual environment, for a period not exceeding 12 months and whose main purpose in visiting is other than an activity remunerated from within the country visited. When data on number of tourists are not available, the number of visitors, which includes tourists, same-day visitors, cruise passengers, and crew members, is shown instead. Sources and collection methods for arrivals differ across countries. In some cases data are from border statistics (police, immigration, and the like) and supplemented by border surveys. In other cases data are from tourism accommodation establishments. For some countries number of arrivals is limited to arrivals by air and for others to arrivals staying in hotels. Some countries include arrivals of nationals residing abroad while others do not. Caution should thus be used in comparing arrivals across countries. The data on inbound tourists refer to the number of arrivals, not to the number of people traveling. Thus a person who makes several trips to a country during a given period is counted each time as a new arrival.

International tourism, expenditures
The below graph shows the total expenditure by international tourism in all countries from 1995 to 2018.
All figures are in billions of U.S. dollars - World data. 1575.3bn total international tourism expenditure in 2018.
Tourism expenditure - International tourism, expenditures (current US$)
International tourism expenditures are expenditures of international outbound visitors in other countries, including payments to foreign carriers for international transport. These expenditures may include those by residents traveling abroad as same-day visitors, except in cases where these are important enough to justify separate classification. For some countries they do not include expenditures for passenger transport items. Data are in current U.S. dollars.

International tourism, expenditures - YOY analysis
The below graph analyzes the year-on-year comparison in expenditure by international tourism.
Increase in total expenditure from 1996 except in 1997, 2001, 2009 and 2015.

Top 10 countries by International tourism expenditures - 2018
China ranked first with $277.3b in international tourism expenditure followed by the United States of America (USA) with $186.5b and Germany with $104.2b in 2018.

International tourism Bivariate map - 2018
Bivariate map which analyzes international tourism combining two different metrics.
Arrivals/Population
Expenditure/Tourism outbound($)
International tourism expenditures are expenditures of international outbound visitors in other countries.

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