Following the formula to determine a 1 year swap rate based on 6 month Euribor, and given latest Euribor rates: 6m Euribor: -0,307% and 1y Euribor -0,191%.

Then,

Z1: 1/(1-0,307%/2) = 1,00153736

Z2= 1/(1-0,191%) = 1,001913655

Therefore annualized 1Y swap rate using formula (1-Z2)/(Z1+Z2) would be -0,191%

Here my question. Checking Reuters EUR 1Y Swap (6m Euribor based) the result is around -0,305%

What am I missing?

Thanks