1800

In 1800, the Second Doctor, Jamie and Zoe visited China. (PROSE: Foreign Devils)

The same year, the Remote completed the transmission tower on Anathema. (PROSE: Interference - Book Two)

Also, the Tenth Doctor and Martha Jones found themselves sailing on the Caribbean Sea when the TARDIS materialised on a schooner. (COMIC: Second Wave)

The total population of New York City was 60,515. (TV: The Gathering)

Behind the scenes
One of the conundrums of Doctor Who fiction is whether there is a "0|year zero" the DWU. If there is, then a year ending in double zeroes — like 1800 — would be the first year of a new century. If, as in real life, there is no year zero, then 1800 would technically be the last year of the 18th century. Though both sides of the argument have been advanced in DWU fiction, this wiki believes — as is clearly spelled out in the 1996 tele-movie — that there is a year zero, and therefore the year 2000 is the start of a new millennium. Second Wave agrees with this, explicitly calling 1800 a part of the 19th century.