Prearranged signs 
 
 

 The following prearranged signs are used in the published tables: 

 Dash (  )  a) when the observed phenomenon does not exist 
  b) when the phenomenon exists and was registered, but there were no occurrences 

 Two little dots ( .. )  in place of numbers smaller than half the minimum order digit 

 Four little dots ( .... )  when the phenomenon exists, but the data are unknown for any reason 

 Hash ( # )  when the value is defined by a ratio and the denominator is equal to zero 

 Colon ( : )  when data are not statistically significant (less than 20 sample observations) 

 Data in brackets ( (123.4) )  when data are statistically less significant (20 to 49 sample observations), i.e. the estimated value must be inserted in brackets 
  
 Dash (  )  a) 
  b) 
  
 Two little dots ( .. )  
  
 Four little dots ( .... )  
  
 Hash ( # )  
  
  
