W h y   d i d   t h i s   h a p p e n ?   W h y   d i d   t h i s   h a p p e n ?   P l e a s e   m a k e   s u r e   y o u r   b r o w s e r   s u p p o r t s   J a v a S c r i p t   a n d   c o o k i e s   a n d   t h a t   y o u   a r e   n o t   b l o c k i n g   t h e m   f r o m   l o a d i n g .   P l e a s e   m a k e   s u r e   y o u r   b r o w s e r   s u p p o r t s   J a v a S c r i p t   a n d   c o o k i e s   a n d   t h a t   y o u   a r e   n o t   b l o c k i n g   t h e m   f r o m   l o a d i n g .   T h e   n u m b e r   o f   e m p t y   u n i t s   i n   t h e   C i t y   o f   L o n d o n   i n c r e a s e d   b y   4 7 %   l a s t   y e a r   a s   t h e   n u m b e r   o f   w o r k e r s   a n d   v i s i t o r s   s l u m p e d ,   a c c o r d i n g   t o   f i g u r e s   f r o m   a n a l y s t s   a t   L o c a l   D a t a   C o m p a n y .
The number of workers and visitors that caused this happened.
( z0 number :ARG0-of ( z1 cause :ARG1 ( z2 this ) ) :quant-of ( z3 and :op ( z4 person :ARG0-of ( z5 work ) ) :op ( z6 person :ARG0-of ( z7 visit ) ) ) )
(z0 / number
    :ARG0-of (z1 / cause-01
                 :ARG1 (z2 / this))
    :quant-of (z3 / and
                  :op1 (z4 / person
                           :ARG0-of (z5 / work-01))
                  :op2 (z6 / person
                           :ARG0-of (z7 / visit-01))))
The number of workers and visitors that caused this happened .
z4 :ARG0-of z5
z3 :op1 z4
z0 :quant-of z3
z3 :op2 z6
z6 :ARG0-of z7
z0 :ARG0-of z1
z1 :ARG1 z2