请教go routine，为什么总是先打印大写字母

package main

import ( "fmt" "runtime" "sync" )

func main() {

// Allocate 1 logical processor for the scheduler to use.
runtime.GOMAXPROCS(1)

// wg is used to wait for the program to finish.
// Add a count of two, one for each goroutine.
var wg sync.WaitGroup
wg.Add(2)

fmt.Println("Start Goroutines")

// Declare an anonymous function and create a goroutine.
go func() {
    // Schedule the call to Done to tell main we are done.
    defer wg.Done()

    // Display the alphabet three times
    for count := 0; count < 3; count++ {
        for char := 'a'; char < 'a'+26; char++ {
            fmt.Printf("%c ", char)
        }
    }
}()

// Declare an anonymous function and create a goroutine.
go func() {
    // Schedule the call to Done to tell main we are done.
    defer wg.Done()

    // Display the alphabet three times
    for count := 0; count < 3; count++ {
        for char := 'A'; char < 'A'+26; char++ {
            fmt.Printf("%c ", char)
        }
    }
}()

// Wait for the goroutines to finish.
fmt.Println("Waiting To Finish")
wg.Wait()

fmt.Println("\nTerminating Program")

}

Start Goroutines

Waiting To Finish

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N OP Q R S T U V W X Y Z a b c d e f g h i j k l m n o p q r s t u v w x y z a b c d e f g h i j k l m n o p q r s t u v w x y z a b c de f g h i j k l m n o p q r s t u v w x y z

Terminating Program

请教，为什么总是大写字母先打印？我觉得应该小写字母先打印啊。