Unlike your local time, internet time is the same all over the world. There are no confusing time zones or daylight savings time shifts to worry about.
There are exactly 1,000 .Beats in a day, making each .Beat precisely 1 minute and 26.4 seconds long.
If you'd like to know how many .Beats are in a year, just multiply 365 days by 1,000 beats/day to get 365,000 .Beats. Good luck figuring out how many seconds are in a year in your head.
If you'd like to know more about .Beats, check out the official Swatch Internet Time page and the Wikipedia page for Swatch Internet Time. There's also a great podcast episode about this system: On The Media #15 - Internet Time. There's also a more pessimistic take at Swatch .Beat - The Failure of Internet Time - Bad Ideas #64.