Operational performance
A Leasing activity
We agreed 205 long-term leases in 2019, amounting to £26 million annual rent, at an average of 1 per cent above previous passing rent (like-for-like units) and in line with valuers’ assumptions. On a net effective basis (net of rent frees and incentives), rents were also 1 per cent ahead of previous rents. The upside from these new lettings added to like-for-like net rental income but was lower in magnitude than the negative impacts from administrations and CVAs and increased vacancy (see financial review on pages 30 to 37).
Our customers continue to focus on increasing their space in prime, high footfall retail and leisure destinations. Significant activity in 2019 included:
—pureplay online brands starting to open stores to increase their physical presence. Morphe, the digital native cosmetics brand, opened three of its six UK stores at intu Victoria Centre, intu Eldon Square and Manchester Arndale, and AliExpress, the consumer platform of Alibaba, opened its first store in Europe at intu Xanadú
—Harrods taking its first shopping centre store, launching a new beauty concept, H Beauty, at intu Lakeside
—a new flagship store for Zara at St David’s, Cardiff, where it is moving into the centre from the high street. This follows the recent upsizing of stores at intu Trafford Centre and intu Lakeside
—leisure brands increasing their space with Puttshack to open its fourth venue at intu Watford, following its successful opening at intu Lakeside. Namco is expanding its range of attractions at intu Metrocentre with Clip ‘n Climb and the first Angry Birds Adventure Golf in the UK and Rock Up is taking space at intu Lakeside
—international fashion brands continuing to expand in the UK with Spanish brand Mango due to open at intu Watford a
B Investment by customers
In the year, 256 units opened or refitted in our centres (2018: 262 stores), representing around 8 per cent of our 3,300 units. Our customers have invested around £125 million in these stores, which we believe is a significant demonstration of their long-term commitment to our centres.
C Rent reviews
We settled 159 rent reviews in 2019 for new rents totalling £45 million, an average uplift of 6 per cent on the previous rents.
D Occupancy
Occupancy was 94.9 per cent, in line with June 2019 (95.1 per cent), but a reduction against 31 December 2018 (96.7 per cent), impacted by units closed in the first half of 2019 from tenants who went into administration or through a CVA process in 2018. This had a 3.7 per cent negative impact on like-for-like net rental income in 2019 from both rents foregone and increased void costs.
E Weighted average unexpired lease term
The weighted average unexpired lease term was 6.3 years (31 December 2018: 7.2 years) illustrating the longevity of our income streams. The reduction against the prior year was primarily due to new lease terms on department stores that have been through a CVA or administration process.
F Footfall
Footfall in our centres increased by 0.3 per cent in the year. UK footfall was flat, significantly outperforming the Springboard footfall monitor for shopping centres which was down on average by 2.5 per cent. We believe this highlights the continued attraction of our compelling destinations against the wider market. In Spain, footfall was up by 3.5 per cent.
G Retailer sales
Estimated retailer sales in our UK centres, which totalled £5.2 billion in 2019, were down 1.6 per cent, impacted by some larger space users who have had difficulties and been through CVAs and those brands who operate successful multichannel models where in-store sales figures take no account of the benefit of the store to online sales. This compares favourably to the British Retail Consortium (BRC), where non-food retailer sales in-store were down 3.1 per cent on average in 2019.
The ratio of rents to estimated sales for standard units remained stable in 2019 at 12.0 per cent. This does not take into account the benefit to the retailer of their multichannel business, such as click and collect.
H Net promoter score
Our net promoter score, a measure of visitor satisfaction, ran consistently high throughout 2019 averaging 75, an increase of 2 over 2018. Visitor satisfaction is paramount to a shopper’s likelihood to visit, which in turn drives footfall and extended dwell time.
I Gross value of community investment
Gross value added, the measure of the economic contribution of intu to the local communities in the UK, remained stable in the year at £4.8 billion.
J Carbon emission intensity reduction
Annual reduction in carbon emission intensity has reduced in 2019. This is due to our continued focus on energy efficiency to reduce our overall energy demand each year, supported by the ongoing greening of the electricity grid as we become less reliant on coal and increase our renewable generation.
Our 2020 target was to reduce carbon emission intensity by 50 per cent, against a 2010 baseline. We reached this target three years ahead of plan and at the end of 2019, our reduction total was 69 per cent.
Table:
 | Notes | 2019 | 201
Leasing activity | A |  | 
— number |  | 205 | 24
— new rent |  | £26m | £39m
— new rent relative to previous passing rent |  | +1% | +6%
Investment by customers | B | £125m | £144m
Rental uplift on rent reviews settled | C | +6% | +7%
Occupancy (EPRA basis) | D | 94.9% | 96.7%
— of which, occupied by tenants trading in administration |  | 2.8% | 2.0%
Unexpired lease term | E | 6.3 years | 7.2 year
Footfall | F | +0.3% | –1.6%
Retailer sales | G | –1.6% | –2.3%
Net promoter score | H | 75 | 7
Gross value added of community investment | I | £4.8bn | £4.8b
Carbon emission intensity reduction | J | 15% | 17%


Question: What is the percentage change in the investment by customers from 2018 to 2019?
Answer: -13.19
Calculation: (125-144)/144