Image copyright PA Image caption The Giant's Causeway was among the three most popular visitor attractions in 2018

Tourism in Northern Ireland remains on track to be a £1bn industry by 2020, the latest official figures suggest.

Estimated spending in 2018 was £968m across five million overnight trips.

Tourism numbers can be difficult to measure accurately from year to year but the data points to a clear upward trend since 2013.

The Giant's Causeway, Titanic Belfast and the Ulster Museum were the three most popular visitor attractions in 2018.

A total of 128 cruise ships docked at Northern Ireland ports in 2018, more than double the number in 2013.

Domestic tourism (trips made by NI residents) was the largest segment of the market, accounting for 44% of trips in 2018.

Great Britain was the next largest (28%), followed by the Republic of Ireland (12%) and the rest of the world (16%).

Image copyright Titanic Belfast Image caption Titanic Belfast was another magnet for tourists

Spending by external tourists (non-NI) in 2018 was estimated to be £669m, a rise of 28% compared to £524m in 2013.

Tourism NI chief executive John McGrillen said "closer to home" markets in the Republic of Ireland and GB were driving spending growth.

He pointed to improved marketing in the Republic influencing those visitors to spend "significantly more".

Other factors which may be helping Northern Ireland tourism include air routes added by Ryanair since 2016, the relative weakness of sterling since the Brexit vote and "screen tourism" driven by Game of Thrones locations.

The last Stormont administration had a target of £1bn of tourism spending by 2020.

Mr McGrillen said the new target should be £2bn by 2030.