Had my car in for its second service recently. Typically, they refilled
the windscreen washer tank and charged me for a litre of washer
antifreeze concentrate. Being an honest bunch they only used half a
litre so left me the rest! I got home and came to put this container
away to discover that exactly the same thing had happened a year or two
ago at my car's first service. I'll be ready for them on the next service!

All that is background to my problem. The washer bottle tells me its
contents are concentrate. So what dilution should be used? The label
has a diagram which I am totally unable to decipher. Here is a photograph:-

http://tinyurl.com/3ga9ym8

What's it telling me please?

TIA
Frank Stacey