This level of planned property sales is higher than any recorded in the past ten years.
According to the NLA, this is the result of recent government changes made to control buy-to-let activity in the private rented sector.
The trade association claimed that policies including a three per cent surcharge on purchases of additional property and the banning of upfront letting fees for tenants have resulted in landlords paying "more than their fair share in tax".
In response, the NLA has created a series of videos exploring topics including how the sector is likely to evolve as the government changes come into effect, how landlords could respond to these reforms, and how tenants could end up paying higher rents and having fewer properties to choose from.
Richard Lambert, CEO of the association, said these videos and the recent research underline the importance of the government looking into how its policy adjustments could impact the private rented sector.
"More and more people are relying on this sector for a home, so it is vital that landlords not only provide a high standard of accommodation, but are incentivised to do so by the prospects of a reasonable return on investment," he added.
"It is our view that these policies are undermining the viability of many landlords' businesses and removing the incentives to invest in residential property for business purposes."
Towards the end of last year, the NLA created a new online platform to help landlords get to grips with new licensing schemes and ongoing consultations that could affect them.