https://www.sipri.org/databases/milex
in 2019$: https://sipri.org/sites/default/files/Data%20for%20all%20countries%20from%201988%E2%80%932020%20in%20constant%20%282019%29%20USD%20%28pdf%29.pdf
in GDP%: https://sipri.org/sites/default/files/Data%20for%20all%20countries%20from%201988%E2%80%932020%20as%20a%20share%20of%20GDP%20%28pdf%29.pdf